TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray absorption spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - European Conference on X-ray Spectrometry 2022
CY - Bruges, Belgium
DA - 27.06.2022
KW - XAS
KW - Mechanochemictry
KW - Time resolved
KW - In situ
PY - 2022
AN - OPUS4-56258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Piotrowiak, T.
A1 - Reinholz, Uwe
A1 - Ludwig, A.
A1 - Emmerling, Franziska
A1 - Streli, C.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Exploring the Depths of Corrosion: A Novel GE-XANES Technique for Investigating Compositionally Complex Alloys
N2 - In this study, we propose the use of nondestructive, depth-resolved, element-specific characterization using grazing exit X-ray absorption near-edge structure spectroscopy (GE-XANES) to investigate the corrosion process in compositionally complex alloys (CCAs). By combining grazing exit X-ray fluorescence spectroscopy (GE-XRF) geometry and a pnCCD detector, we provide a scanning-free, nondestructive, depth-resolved analysis in a sub-micrometer depth range, which is especially relevant for layered materials, such as corroded CCAs. Our setup allows for spatial and energy-resolved measurements and directly extracts the desired fluorescence line, free from scattering events and other overlapping lines. We demonstrate the potential of our approach on a compositionally complex CrCoNi alloy and a layered reference sample with known composition and specific layer thickness. Our findings indicate that this new GE-XANES approach has exciting opportunities for studying surface catalysis and corrosion processes in real-world materials.
KW - Degradation mechanisms
KW - Grazin exit XANES
KW - Depth resolved XANES
KW - Compositional complex alloys
KW - Corrosion
PY - 2023
DO - https://doi.org/10.1021/acs.analchem.3c00404
VL - 95
SP - 4810
EP - 4818
PB - ACS Publications
AN - OPUS4-57823
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Recycled transition metal phosphates as functional materials for electrochemistry
N2 - In the last decade transition metal phosphates (TMPs) captured major interest due to their high electrochemical activity useful for electrode materials, supercapacitors or batteries. Importantly, TMPs are known to exhibit high proton conductivity of the order of >10-2 -10-5 S/cm from 25°C to temperatures as high as 400°C. The crucial milestone in the research on the applicational use of TMPs in all their varieties is an ability to obtain, explore and optimize different compositions and structures, both crystalline and amorphous. Thus, we elucidate the structures of amorphous and crystalline Ni- and Co phosphate phases, as they develop upon heating. This method relies on the thermal decomposition of a crystalline M-struvite precursor, i.e. NH4MPO4•6H2O (M = Mg, Ni, Co, NixCo1-x etc. Here, coincidently volatile components such as H2O or NH3 degas out of the compound resulting in a phase transformation to amorphous or crystalline metal phosphate phases depending on the reaction conditions.
For this we used a suite of advanced methods such as FTIR, FT-RS and synchrotron-based XAS. Ni-struvite transforms to amorphous phases over a broad range of temperatures (90°C < T < 600°C) in which it remains in an octahedral coordination environment. On the other hand, Co-struvite treatment leads to multiple crystalline phases with only small amounts of short-lived amorphous phases.
Importantly, the occurring amorphous phases exhibit uniform mesoporous frameworks (2–5 nm wide pore channels, specific surface area of 100 m2g−1 and a pore volume of 0.13 cm3g−1) at low temperatures (<200°C) while the crystalline compounds can be used as proton conductors demonstrating values of >10-4 S/cm at 25°C. Consequently, we investigated the amorphization/evolution of mesoporosity, the proton-conducting properties and the complex local structure with in- and ex-situ approaches during thermal treatment. Additionally, to this low cost, environmentally friendly and simple one pot synthesis, the precursor M-struvites could grow as a recovery product from industrial waste waters. In such a way, they would to a recycling economy of sought-after commodities like phosphorus or transition metals.
T2 - E-MRS Spring Conference 2023
CY - Strasbourg, France
DA - 29.05.2023
KW - Struvite
KW - Transition metals
KW - Phosphates
KW - Functional materials
KW - Mesoporosity
KW - Proton conductivity
PY - 2023
AN - OPUS4-57587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Evolution of mesoporous frameworks from precipitated struvite-structured metal phosphate materials
N2 - Mesoporous transition metal phosphates (TMPs) have attracted major interest due to their high (electro-)catalytic activity suitable for H2 generation, supercapacitors or batteries. Typically, mesoporous materials are synthesized via a template-based route. This way is in the case of TMP because the surfactants used are difficult to remove due to the sensitivity of the mesoporous framework. We present a template-free method including the formation of a precursor phase called M-struvite (NH4MPO4•6H2O, M = Mg2+, Ni2+, Co2+, Ni2+xCo2+1-x) to synthesize mesoporous and amorphous metal phosphates. This method relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneous mesoporous phase associated with the degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the coordination metal coordination environment was followed with diffraction and spectroscopy based in-situ and ex-situ methods. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions between the chemical systems. In a complex amorphous structure, thermal decomposed Mg-, Ni- and NixCo1-x-struvites exhibit high surface areas and pore volumes for phosphate materials with a spherical to channel-like pore geometry (240 m²g-1 and 0.32 cm-3 g-1 for Mg and 90 m²g-1 and 0.13 cm-3 g-1 for Ni). In addition to this low-cost, environmentally friendly and simple synthesis, M-struvites could grow as a recycling product from industrial and agricultural wastewaters. These waste products could be upcycled through a simple thermal treatment for further applications.
T2 - ECCG7, European Conference on Crystal Growth
CY - Paris, France
DA - 25.07.2022
KW - Transition metals
KW - Phosphates
KW - Struvite
KW - Amorphous phases
KW - Mesoporosity
PY - 2022
AN - OPUS4-55491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
N2 - Jobflow is a free, open-source library for writing and executing workflows. Complex workflows can be defined using simple python functions and executed locally or on arbitrary computing resources using the FireWorks workflow manager.
Some features that distinguish jobflow are dynamic workflows, easy compositing and connecting of workflows, and the ability to store workflow outputs across multiple databases.
KW - Automation
KW - Workflows
KW - Computational Materials Science
PY - 2024
DO - https://doi.org/10.5281/zenodo.10466868
PB - Zenodo
CY - Geneva
AN - OPUS4-59313
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ueltzen, Katharina
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Benner, Philipp
A1 - George, Janine
T1 - Software and data repository: Can simple exchange heuristics guide us in predicting magnetic properties of solids?
N2 - Software and data for the publication "Can simple exchange heuristics guide us in predicting magnetic properties of solids?" Release that corresponds to the first preprint version of the article. Full Changelog: https://github.com/DigiMatChem/paper-exchange-heuristics-in-magnetic-materials/commits/v1.0.0
KW - Magnetism
KW - Machine Learning
KW - Materials Design
KW - Chemically Complex Materials
KW - Sustainable Materials Design
PY - 2025
DO - https://doi.org/10.5281/zenodo.16811104
PB - Zenodo
CY - Geneva
AN - OPUS4-64672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts.
T2 - Advances in Magnetics (AIM) 2025
CY - Bressanone, Italy
DA - 10.02.2025
KW - Energy harvesting
KW - Thermomagnetic energy conversion
KW - Magnetic materials
PY - 2025
AN - OPUS4-65201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts. Furthermore, we will review criticality issues of materials employed in this new technology.
T2 - MRS Spring Meeting Seattle
CY - Seattle, WA, USA
DA - 07.04.2025
KW - Energy harvesting
KW - Magnetic materials
KW - Thermomagnetic energy conversion
PY - 2025
AN - OPUS4-65198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts. Furthermore, we will review criticality issues of materials employed in this new technology.
T2 - MRS Fall Meeting Boston
CY - Boston, MA, USA
DA - 01.12.2025
KW - Energy harvesting
KW - Thermomagnetic energy conversion
KW - Magnetic materials
PY - 2025
AN - OPUS4-65197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from their microstructure
N2 - The international research community is currently devoting extensive resources to the development of digital material data spaces and the associated digital twins and product passports of materials and components. A common weak link in these projects to date has been the connection between physical components / samples and their digital data and documents. This is where the concept of the unique identification comes in. Components produced using additive manufacturing can be marked for unique identification and secure authentication [1,2]. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (i.e., a digital product passport) to the actual components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface or the internal cavity of hollow components. However, local manipulation of components may alter the properties, and external tagging features can be altered or even removed by post-processing treatments.
This work provides a new methodology for identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. X-ray computed tomography (XCT) was employed to image the microstructural features of a batch of AlSi10Mg parts. Based on size and geometry, the most prominent features were selected to create a unique digital authenticator. We implemented a framework in Python using open-access modules that can successfully create a digital object authenticator using the segmented microstructure information from XCT. We show that this method allows to authenticate individual parts from the build job based on its microstructural fingerprint. This is our contribution to enhancing the security and product protection of additively manufactured components.
T2 - FEMS EUROMAT
CY - Granada, Spain
DA - 15.09.2025
KW - Authentication
KW - Fingerprint
KW - Non-destructive testing
PY - 2025
AN - OPUS4-65202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from their microstructure
N2 - Components produced using additive manufacturing can be marked for unique identification and secure authentication [1,2]. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (i.e., a digital product passport) to the actual components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface of the internal cavity of hollow components. However, local manipulation of components may alter the properties, and external tagging features can be altered or even removed by post-processing treatments. This work therefore aims to provide a new methodology for identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. X-ray computed tomography (XCT) was employed to image the microstructural features of AlSi10Mg parts. Based on size and geometry, the most prominent features were selected to create a unique digital authenticator. We implemented a framework in Python using open-access modules that can successfully create a digital object authenticator using the segmented microstructure information from XCT. The authenticator is stored as a QR code, along with the 3D information of the selected features.
T2 - MRS Spring Meeting Seattle
CY - Seattle, WA, USA
DA - 07.04.2025
KW - Additive Manufacturing
KW - Fingerprint
KW - Non-destructive testing
PY - 2025
AN - OPUS4-65199
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hein-Paar, Jakob
T1 - Spectroscopic Insights into the Reactivity of Energetic Materials
N2 - Energetic materials (explosives, propellants, pyrotechnics, and gas generators; EM) release large amounts of energy when initiated by mechanical loading and have many technological applications including in energy storage and propulsion. The accidental initiation of an EM – particularly in the wrong setting – has the potential to be catastrophic. Unfortunately, there is little understood about what determines the sensitivity of a given EM. This poses severe restrictions on our ability to design new and safer EMs.
Aiming to better understand the initiation mechanisms of EMs, we here investigate the reactivity of simple, isomorphous azides (MN3 M=Li, Na). Both metal azides contain the same explosophoric azido anions, but differ significantly in their reactivity, presumably owing to different bonding interactions between the anion and the metal cation. This interaction offers a promising probe for X-ray spectroscopy and quantum chemical simulations. In noting that mechanical initiation results from mechanical impact – with high local pressures – we are particularly interested in identifying how this bonding interaction changes as a function of pressure.
This interaction offers a promising probe for X-ray spectroscopy and quantum chemical simulations. In noting that mechanical initiation results from mechanical impact – with high local pressures – we are particularly interested in identifying how this bonding interaction changes as a function of pressure.
Here we show results from DFT simulations that indicate a shift in electronic structure and changes in the metal-azide bond with increasing pressure, which is further investigated through experimental XAS spectra. Together, our results show promising insights into the behaviour of simple metal azide EMs.
T2 - SXR2023 - Principles of Functionality From Soft X-Ray Spectroscopy
CY - Berlin, Germany
DA - 11.09.2023
KW - Energetic materials
PY - 2023
AN - OPUS4-58824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falk, Florian
A1 - Sobol, Oded
A1 - Stephan-Scherb, Christiane
T1 - The impact of the microstructure of Fe-16Cr-0.2C on high-temperature oxidation – sulphidation in SO2
N2 - This study elucidates the impact of the microstructure of Fe-16Cr-0.2C on oxide layer formation at 650 ◦C in Ar-0.5 % SO2. A cold-rolled and two heat-treated states of the alloy were exposed for up to 1000 h. The samples were characterised in detail from microstructural and chemical perspectives using scanning electron microscopy (SEM), X-ray diffraction (XRD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The microstructural modification of the alloy by heat-treatment was advantageous. It was found that Cr-carbides support chromia formation and reduce sulphidation when their area fraction is low and diameter is small.
KW - Steel
KW - Iron
KW - SIMS
KW - SEM
KW - High temperature corrosion
KW - Oxidation
KW - Sulphidation
PY - 2021
DO - https://doi.org/10.1016/j.corsci.2021.109618
VL - 190
SP - 109618
PB - Elsevier Ltd.
AN - OPUS4-53001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Röhsler, Andreas
A1 - Sobol, Oded
A1 - Hänninen, H.
A1 - Böllinghaus, Thomas
T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load
N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress.
KW - ToF-SIMS
KW - Hydrogen
KW - Deuterium
KW - AISI 304L
KW - EBSD
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142
DO - https://doi.org/10.1038/s41598-020-60370-2
VL - 10
IS - 1
SP - 3611
PB - Nature
AN - OPUS4-50514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steiner, S.
A1 - Heldt, J.
A1 - Sobol, Oded
A1 - Unger, Wolfgang
A1 - Frömeling, T.
T1 - Influence of oxygen vacancies on core-shell formation in solid solutions of (Na,Bi)TiO3 and SrTiO3
N2 - Solid solutions of (Na,Bi)TiO3 (NBT) and SrTiO3 (ST) are materials of interest for high-strain or high-energy density capacitor applications. Often, they exhibit chemical heterogeneity and develop core-shell structures during regular solid-state synthesis with an NBT-rich core. In this case, the NBT forms first so that the strontium needs to diffuse into the material to reach chemical homogeneity. Depending on the presence of core-shell structures, the electrical properties can vary drastically. In this work, we rationalize the effect of variations in oxygen vacancy concentration by Fe-acceptor and Nb-donor doping. It can be shown that a diffusion couple of strontium and oxygen is responsible for chemical homogenization and that the oxygen vacancy content can control the formation of a core-shell structure.
KW - Lead-free ceramics
KW - Bismuth titanates
KW - Core-shell structures
KW - Diffusion/diffusivity
KW - Ferroelectricity/ferroelectric materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525988
DO - https://doi.org/10.1111/jace.17845
SP - 1
EP - 10
PB - Wiley Periodicals LLC, John Wiley & Sons, Inc.
AN - OPUS4-52598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Dynamics of Composite Materials
N2 - Historically, to tune the properties of a polymer or more general soft matter systems by a second phase is not a new concept and dates back to the 40s of the last century. Beside some successes, the improvement of the properties remained somehow limited. The expectations of the enhancement of the properties of composites changed by the developments of Toyota Central research in the 1990s. It was shown that the incorporation of 5 vol% exfoliated layers of a clay system into a polymer leads to a strong improvement of the mechanical and thermal properties. This discovery stimulated a broad research interest of both fundamental and applied character. Today, polymer-based nanocomposites have reached a billion-dollar global market. The corresponding applications span from components for transportation, commodity plastics with enhanced barrier and/or flame retardancy characteristics, to polymers with electrical properties for shielding, electronics, sensors, and solar cells as well as to live science. Important fields are filled rubbers, reinforced thermoplastics, or thermosets for automotive, aircraft/space and marine industries, but also membranes for separation processes as well as barrier layers, just to mention a few.
For a variety of applications, the molecular mobility in nanocomposites is of great importance. This concerns the molecular mobility needed to form a percolating filler network in rubbers used in tires or in composites employed in electric shielding applications. In general, it is also essential for processing polymer-based nanocomposites. Furthermore, separation processes in composite materials for membranes require a certain molecular mobility. This also concern nanodielectrics used in electrical applications or sensors where the mobility of charge carriers can be related to the fluctuations of molecular groups etc. Finally, the molecular mobility can be taken as probe for structure on a molecular scale.
Broadband dielectric spectroscopy is a powerful tool to investigate the molecular mobility in polymer systems. It is due to the extremely broad frequency and sensitivity range that can be covered by this technique. Information about localized and cooperative molecular fluctuations, polarization effects at interfaces, as well as charge transport processes can be deduced. Therefore, this book focusses on broadband dielectric spectroscopy of composite materials. Moreover, the dielectric studies are accompanied by mechanical spectroscopy, advanced calorimetry, NMR techniques, as well as transmission electron microscopy and X-ray scattering investigations.
Besides a brief introduction to (nano)composites, the book aims to address fundamental aspects of the molecular mobility in this innovative group of materials. Selected examples with scientific interest and some cases with high industrial impact were chosen. Due to the breadth of the subject, unfortunately not all topics could be addressed in detail, such as processing for instance.
Berlin, Andreas Schönhals
July 2021 Paulina Szymoniak
KW - Composite materials
KW - Nanocomposites
PY - 2022
SN - 978-3-030-89722-2
SN - 978-3-030-89723-9
DO - https://doi.org/10.1007/978-3-030-89723-9
VL - 2022
SP - 1
EP - 375
PB - Springer Nature
CY - Cham, Switzerland
AN - OPUS4-54538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Dietrich, P. M.
A1 - Radnik, Jörg
T1 - In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy
N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS xperiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.
KW - DNA
KW - XPS
KW - NAP-XPS
KW - Radiation damage
KW - Single-strand break (SSB)
KW - Double-strand break (DSB)
KW - Xray
KW - OH radical
KW - Hydroxyl radical
KW - LEE
KW - Low energy electrons
KW - Dosimetry
KW - Geant4
KW - Geant4-DNA
KW - TOPAS
KW - TOPAS-nbio
KW - Microdosimetry
KW - DNA radiation damage
KW - Direct damage
KW - Indirect damage
KW - Quasi-direct damage
KW - Hydration shell
KW - Dry DNA
KW - Hydrated DNA
KW - ROS
KW - Radical
KW - Reactive oxygen species
KW - Net-ionization reaction
KW - Radiation therapy
KW - Cancer therapy
KW - Xray photo electron spectrocopy
KW - Near ambient pressure xray photo electron spectroscopy
KW - Base damage
KW - Base loss
KW - Dissociative electron transfer (DET)
KW - Dissociative electron attachment (DEA)
KW - Hydrated electron
KW - Prehydrated electron
KW - Ionization
KW - PES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524060
DO - https://doi.org/10.1038/s42004-021-00487-1
SN - 2399-3669
VL - 4
IS - 1
SP - 50
PB - Springer Nature
CY - London
AN - OPUS4-52406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohammadifar, E.
A1 - Ahmadi, V.
A1 - Gholami, M.F.
A1 - Oehrl, A.
A1 - Kolyvushko, O.
A1 - Nie, C.
A1 - Donskyi, Ievgen
A1 - Herziger, S.
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Böttcher, C.
A1 - Rabe, J.P.
A1 - Osterrieder, K.
A1 - Azab, W.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Graphene-Assisted Synthesis of 2D Polyglycerols as Innovative Platforms for Multivalent Virus Interactions
N2 - 2D nanomaterials have garnered widespread attention in biomedicine and
bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional
groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex
virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.2D nanomaterials have garnered widespread attention in biomedicine and bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.
KW - 2D Materials
KW - Graphene template
KW - Multivalency
KW - Polyglycerol
KW - Virus inhibition
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527726
DO - https://doi.org/10.1002/adfm.202009003
VL - 31
IS - 32
SP - 2009003
PB - Wiley VCH
AN - OPUS4-52772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jungnickel, R.
A1 - Mirabella, Francesca
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Balasubramanian, K.
T1 - Graphene‑on‑gold surface plasmon resonance sensors resilient to high‑temperature annealing
N2 - Gold films coated with a graphene sheet are being widely used as sensors for the detection of label-free binding interactions using surface plasmon resonance (SPR). During the preparation of such sensors, it is often essential to subject the sensor chips to a high-temperature treatment in order to ensure a clean graphene surface. However, sensor chips used currently, which often use chromium as an adhesion promoter, cannot be subjected to temperatures above 250 °C, because under such conditions, chromium is found to reorganize and diffuse to the surface, where it is easily oxidized, impairing the quality of SPR spectra. Here we present an optimized preparation strategy involving a three-cycle tempering coupled with chromium (oxide) etching, which allows the graphene-coated SPR chips to be annealed up to 500 °C with little deterioration of the surface morphology. In addition, the treatment delivers a surface that shows a clear enhancement in spectral response together with a good refractive index sensitivity. We demonstrate the applicability of our sensors by studying the kinetics of avidin–biotin binding at different pH repeatedly on the same chip. The possibility to anneal can be exploited to recover the original surface after sensing trials, which allowed us to reuse the sensor for at least six cycles of biomolecule adsorption.
KW - Surface plasmon resonance
KW - Graphene
KW - Sensing
KW - Surface regeneration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564585
DO - https://doi.org/10.1007/s00216-022-04450-4
SN - 1618-2642
SP - 1
EP - 7
PB - Springer
AN - OPUS4-56458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nickl, Philip
A1 - Hilal, T.
A1 - Olal, D.
A1 - Donskyi, Ievgen
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Haag, R.
T1 - A New Support Film for Cryo Electron Microscopy Protein Structure Analysis Based on Covalently Functionalized Graphene
N2 - Protein adsorption at the air–water interface is a serious problem in cryogenic electron microscopy (cryoEM) as it restricts particle orientations in the vitrified ice-film and promotes protein denaturation. To address this issue, the preparation of a graphene-based modified support film for coverage of conventional holey carbon transmission electron microscopy (TEM) grids is presented. The chemical modification of graphene sheets enables the universal covalent anchoring of unmodified proteins via inherent surface-exposed lysine or cysteine residues in a one-step reaction. Langmuir–Blodgett (LB) trough approach is applied for deposition of functionalized graphene sheets onto commercially available holey carbon TEM grids. The application of the modified TEM grids in single particle analysis (SPA) shows high protein binding to the surface of the graphene-based support film. Suitability for high resolution structure determination is confirmed by SPA of apoferritin. Prevention of protein denaturation at the air–water interface and improvement of particle orientations is shown using human 20S proteasome, demonstrating the potential of the support film for structural biology.
KW - Functionalized graphene
KW - Transmission electron microsocpy
KW - Protein structure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566443
DO - https://doi.org/10.1002/smll.202205932
SN - 1613-6810
SP - 2205932
PB - Wiley VCH
AN - OPUS4-56644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Radnik, Jörg
A1 - Dietrich, Paul M.
A1 - Seitz, Harald
A1 - Hahn, Marc Benjamin
T1 - Radiation damage to amino acids, peptides and DNA-binding proteins: the influence of water directly monitored by X-ray photoelectron spectroscopy
N2 - Ionizing radiation damage to biomolecules plays a crucial role in radiotherapy as a cancer treatment. Among these, DNA-binding proteins are of particular interest due to their pivotal roles in shielding DNA and facilitating its repair. Hence, in this study, we present first-ever recorded data of radiation damage to a protein monitored directly with near-ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS) under a water atmosphere. This surface sensitive technique was used to in situ damage and probe gene-V protein (G5P, a model DNA-binding protein) under wet NAP conditions and dry vacuum (UHV) conditions to determine the effect of water on the radiation response. In addition, the X-ray radiation damage to selected pure amino acids and short homopeptides was determined to better understand the variety of damage mechanisms within the complex protein. In dry samples, drastic chemical changes were detected in all biomolecules dominated by fragmentation processes. Here, the breakage of peptide
bonds in the peptides and the protein are dominant. Surprisingly, hydration – despite introducing additional indirect damage pathways via water radiolysis – led to a reduction in overall radiation damage. This behaviour was attributed to hydration-dependent changes in reaction rates and respective deexcitation and damaging channels within the molecules and secondary species such as low-energy (LEE), (pre)-hydrated/(pre)-solvated electrons and radical species such as hydroxyl radicals.
KW - Radiation damage
KW - (Near-ambient pressure) X-ray photoelectron spectroscopy
KW - Ultra-high vacuum
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647565
DO - https://doi.org/10.1039/d5cp01887k
VL - 27
IS - 48
SP - 1
EP - 22
PB - Royal Society of Chemistry
AN - OPUS4-64756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amiri, Hesam
A1 - Nikookhesal, Aidin
A1 - Murugan, Divagar
A1 - Scholz, Stefan
A1 - Frentzen, Michael
A1 - Cao, Yuan
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Vu, Xuan-Thang
A1 - Narayanan, Madaboosi S.
A1 - Knoch, Joachim
A1 - Ingebrandt, Sven
A1 - Adeli, Mohsen
A1 - Pachauri, Vivek
T1 - High precision correlative analysis of dielectric behavior evolution and anisotropy in graphene oxide thin film as a function of thermal annealing parameters
N2 - Graphene oxide (GO) and reduced graphene oxide (rGO) attract keen interest from different science and technology sectors owing to their tunable material characteristics dependent on C/O ratio. Thermal annealing in different gaseous environments serves as an effective approach to manipulate the C/O ratio in graphitic lattice, making it suitable for various electronic, optical and composites applications. Despite regular use of thermal annealing, systematic studies on dielectric properties evolution in GO against different annealing parameters remain elusive. This work reports on a reliable approach that adopts a joint Raman Spectroscopy, Mueller Matrix Spectroscopic Ellipsometry (MMSE) and high-precision electrical impedance spectroscopy (HP-EIS) framework for studying the evolution of dielectric behavior and anisotropies in GO. The experimental platform involved lithography-defined GO patterns connected to metal microelectrodes and glass passivation for protection from gaseous environments during annealing and measurements using Raman, MMSE and HP-EIS. The presented study delineates the effects of annealing parameters such as temperature, heating rate, and gaseous environment on GO permittivity. Novel findings include the discovery of a direct relationship between heating rate and dielectric properties, as well as determination of vertical limitation of MMSE for permittivity distribution characterization in GO, for the first time, to be around 8 nm.
KW - Thermal annealing
KW - Reduced graphene oxide
KW - Thin films
KW - 2D materials
KW - Spectroscopic ellipsometry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652428
DO - https://doi.org/10.1016/j.nwnano.2025.100130
SN - 2666-9781
VL - 11
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Rajotte, Isabelle
A1 - Thibeault, Marie-Pier
A1 - Sander, Philipp C.
A1 - Kodra, Oltion
A1 - Lopinski, Gregory
A1 - Radnik, Jörg
A1 - Johnston, Linda J.
A1 - Brinkmann, Andreas
A1 - Resch-Genger, Ute
T1 - Quantifying surface groups on aminated silica nanoparticles of different size, surface chemistry, and porosity with solution NMR, XPS, optical assays, and potentiometric titration
N2 - We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
KW - Advanced Materials
KW - Amino Groups
KW - Calibration
KW - Characterization
KW - Functional groups
KW - Method Comparison
KW - Nano Particle
KW - Validation
KW - XPS
KW - Optical Assay
KW - Quantification
KW - Surface Analysis
KW - Reference Materials
KW - Synthesis
KW - Fluorescence
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649992
DO - https://doi.org/10.1039/d5na00794a
VL - 7
IS - 21
SP - 6888
EP - 6900
PB - Royal Society of Chemistry
AN - OPUS4-64999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schusterbauer, Robert
A1 - Schünemann, Pia
A1 - Nickl, Philip
A1 - Er, Jasmin
A1 - Kämmer, Victoria
A1 - Junge, Florian
A1 - Fazzani, Salim
A1 - Mrkwitschka, Paul
A1 - Meermann, Björn
A1 - Haag, Rainer
A1 - Donskyi, Ievgen
T1 - Bifunctional Reduced Graphene Oxide Derivatives for PFOA Adsorption
N2 - Innovative materials are crucial for removing persistent pollutants per‐ and polyfluorinated alkyl substances (PFAS) from water. Here, a novel bifunctional reduced graphene oxide (TRGO) adsorbent is developed and characterized by advanced surface sensitive methods. Compared to pristine TRGO, the functionalized TRGO shows markedly improved PFAS removal efficiency and demonstrates strong potential for water purification applications.
KW - Adsorber
KW - PFAS
KW - HR-CS-GFMAS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651238
DO - https://doi.org/10.1002/ceur.202500240
SN - 2751-4765
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-65123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - The emp project smurfnano – Standardizing the quantification of surface functionalities, ligands, and coatings on nanomaterials
N2 - For industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage, meanwhile engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - LNE Workshop
CY - Paris, France
DA - 04.11.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
AN - OPUS4-64725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smerechuk, Anastasiia
A1 - Guilherme Buzanich, Ana
A1 - Büchner, Bernd
A1 - Wurmehl, Sabine
A1 - Morrow, Ryan
T1 - Synthesis and properties of Sr2La2NiW2O12, a new S = 1 triangular lattice magnet
N2 - Magnetic materials featuring triangular arrangements of spins are frequently investigated as platforms hosting magnetic frustration. Hexagonal perovskites with ordered vacancies serve as excellent candidates for two-dimensional triangular magnetism due to the considerable separation of the magnetic planes. In this work, the effects of chemical pressure on the ferromagnetic ground state of Ba2La2NiW2O12 by substitution of Ba2+ with Sr2+ to produce Sr2La2NiW2O12 are investigated. The two materials are characterized using synchrotron-based XRD, XANES and EXAFS in addition to magnetometry in order to correlate their crystal structures and magnetic properties. Both materials form in space group R 3, yet as a result of the enhanced bending of key bond angles due to the effects of chemical pressure, the T C value of the magnetic Ni2+ sublattice is reduced from ∼6 K in Ba2La2NiW2O12 to 4 K in Sr2La2NiW2O12.
KW - XRD
KW - Magnetic materials
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652982
DO - https://doi.org/10.1107/S2052520624007091
SN - 2052-5206
VL - 80
IS - 5
SP - 467
EP - 473
PB - International Union of Crystallography (IUCr)
AN - OPUS4-65298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Interlaboratory comparisons as tool in advanced materials characterisation
N2 - Interlaboratory comparisons (ILCs) are an important tool for the validation of characterisation methods, and, herwith, a prerequisite for standardisation. The "Versailles Project on Advanced Materials and Standards" offers a framework for performing such ILCs: (i) TiO2 nanoparticles using ToF-SIMS, and (ii) the chemical composition of functionalized graphene using XPS. The results of both ILCs underline the importance of sample preparation for the measured results.
T2 - NanoMeasure France Meeting
CY - Online meeting
DA - 07.06.2024
KW - Standardisation
KW - Validation
KW - Interlaboratory comparison
KW - Graphene related 2D materials
KW - Titania nanoparticles
PY - 2024
AN - OPUS4-60532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - How to expand the use of your test method? Validation is key towards standardisation
N2 - Standardised methods need validation. The main validation parameters like trueness, repeatability and intermediate precision and reproducibility are presented. Furthermore, different methods for the validation are disussed: (certified) reference materials, representative testing materials and interlaboratory comparisons. At last, the need of proficiency testing is stressed.
T2 - Materials Week 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Validation
KW - Reproducibility crisis
KW - Metrological traceability
KW - Measurement uncertainty
PY - 2024
AN - OPUS4-60536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardised Measurements of Surface Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods.
T2 - European Partnership on Metrology 2023 Review Conference
CY - Amsterdam, Netherlands
DA - 07.11.2023
KW - Surface chemistry
KW - Quality assurance
KW - Traceability
PY - 2023
AN - OPUS4-59142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scholtz, Lena
T1 - Standardized Measurements of Surface Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely and commonly fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, their interaction with biological species, and also their environmental fate are largely determined by the surface functionalities of the particles. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, determination of their applicability, and mandatory to meet increasing concerns regarding their safety. In addition, industry as well as international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized up until now. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR), as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter, typically less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required to provide well characterized test and reference nanomaterials including benchmark values.[1] These needs are addressed by the current European metrology project SMURFnano, involving 12 partners from different National Metrology Institutes, designated and research institutes, two university groups as well as one large company and one SME producing NPs. This project, as well as first results derived from the development of test and reference materials with a well characterized surface chemistry, and ongoing interlaboratory comparisons, will be presented.
T2 - eMRS - Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Nano
KW - Particle
KW - Silica
KW - Polymer
KW - Metrology
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - qNMR
KW - Validation
KW - Potentiometry
KW - XPS
PY - 2025
AN - OPUS4-64243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized TiO2 D540 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized TiO2 D540 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - TiO2 D540 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7961317
PB - Zenodo
CY - Geneva
AN - OPUS4-57669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Analytical & Characterisation Excellence in nanomaterial risk assessment: A tiered approach
N2 - The work packages of the EU H2020 project ACEnano are presented and their activities in standardization and guidance for regulators and SMEs.
T2 - ISO/TC 229 Strategy meeting
CY - Online meeting
DA - 10.11.2020
KW - Nanomaterials
KW - Standardization
KW - Risk assessment
PY - 2020
AN - OPUS4-51611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized ZnO nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized ZnO nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - ZnO nanoparticles
KW - NanoSolveIT
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990301
PB - Zenodo
CY - Geneva
AN - OPUS4-57661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized CeO2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized CeO2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - CeO2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941461
PB - Zenodo
CY - Geneva
AN - OPUS4-57667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Advanced Materials for the Energy Transition
N2 - Advanced Materials are crucial for the sucess of the energy transition. 10 relevant advanced materials were chosen and their role for relevant technologies was analysed. Challenges regarding their safe and sustainable use are discussed.
T2 - OECD WPMN SG Advanced Materials Teleconference
CY - Online meeting
DA - 30.09.2025
KW - Solar Cells
KW - Advanced Carbon Materials
KW - Fuel Cells
KW - Batteries
KW - Hydrogen Storage
PY - 2025
AN - OPUS4-64306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reed, B.P.
A1 - Marchesini, S.
A1 - Chemello, Giovanni
A1 - Morgan, D.J.
A1 - Vyas, N.
A1 - Howe, T.
A1 - Radnik, Jörg
A1 - Clifford, C,A.
A1 - Pollard, A.J.
T1 - The influence of sample preparation on XPS quantification of oxygen-functionalised graphene nanoplatelets
N2 - X-ray photoelectron spectroscopy (XPS) is widely used for characterising the chemistry of graphene-related two-dimensional materials (GR2M), however the careful preparation of the sample for analysis is important in obtaining representative quantifications. We report an investigation by three laboratories showing that the preparation method for oxygen-functionalised graphene nanoplatelet (GNP) powders has a significant effect on the homogeneous-equivalent elemental composition measured in XPS. We show that pressing GNP powders onto adhesive tapes, into recesses, or into solid pellets results in inconsistencies in the XPS quantification. The measured oxygen-to-carbon atomic ratio from GNP pellets depends upon the die pressure used to form them and the morphology of the GNPs themselves. We recommend that powder samples of GR2Ms are pelletised prior to XPS analysis to improve repeatability and reproducibility of measurements.
KW - X-ray photoelectron spectroscopy
KW - Graphene related two-dimensional materials (GR2M)
KW - Pelletization
KW - Powder
PY - 2023
DO - https://doi.org/10.1016/j.carbon.2023.118054
SN - 0008-6223
VL - 211
SP - 1
EP - 6
PB - Elsevier Ltd.
AN - OPUS4-57694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hülagü, Deniz
A1 - Hirahara, Kenta
A1 - Fischer, Daniel
A1 - Florian, Camilo
A1 - Schusterbauer, Robert
A1 - Ermilova, Elena
A1 - Krüger, Jörg
A1 - Unterreiner, Andreas-Neil
A1 - Bonse, Jörn
A1 - Hertwig, Andreas
T1 - Using imaging ellipsometry to understand femtosecond laser materials processing of group IV materials
N2 - Laser materials processing is an important tool for creating and shaping new materials. Laser machining, especially with ultrashort pulses offers the modification of surfaces, thin coatings, and bulk materials with an unprecedented precision and control. The most desired feature of pulsed laser processing in the femtosecond range is that the heat-affected zone in the irradiated material will be extremely small. To better understand the mechanisms involved during laser irradiation, it is important to analyse the outcome of light-matter interaction with spectroscopic methods. Ellipsometry, especially spectroscopic imaging ellipsometry (SIE), has become an important tool for this in recent times, as it gives access to local layer thicknesses, materials dielectric functions, and features like changes in surface roughness.
This work includes an overview over our recent studies examining near-infrared fs-laser surface processing of different group IV materials. The superficial phase change of silicon from crystalline to amorphous has been investigated in the past as the result of laser processing strongly depends on the crystal orientation. Moreover, SIE is capable of determining the
properties of buried a-Si interfaces with micrometer lateral and sub-nanoneter vertical precision. Additionally, the growth of native and laser-induced oxides can be revealed.
T2 - ICSE10 - 10th International Conference on Spectroscopic Ellipsometry
CY - Boulder, CO, USA
DA - 08.06.2025
KW - Laser surface ablation
KW - Amorphous Carbon
KW - Silicon
KW - Correlative Imaging Ellipsometry
PY - 2025
AN - OPUS4-63633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Co2.25Fe0.75O4 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7940538
PB - Zenodo
CY - Geneva
AN - OPUS4-57663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - The SMURFnano project - standardized measurements of surface functionalities on nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, optoelectronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required and well characterized test and reference nanomaterials providing benchmark values.[1] These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - eMRS
CY - Strasbourg, France
DA - 27.05.2025
KW - Quality assurance
KW - Reference analysis
KW - Standardization
KW - Metrology
KW - Reference products
KW - Reference materials
KW - Mission
KW - Surface chemistry
KW - Nano
KW - Particle
KW - qNMR
KW - XPS
KW - Fluorescence
KW - Optical assays
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-63243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Tavernaro, Isabella
A1 - Abram, Sarah-Luise
A1 - Homann, Christian
A1 - Scholtz, Lena
A1 - Radnik, Jörg
T1 - Validated and standardized measurements and quantification of surface functionalities on nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. Nanoparticle function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. Industry, e.g., must comply with various regulations, including the chemicals´ regulation REACH (2006/1907) and cosmetic products regulation (2009/1223), depending on the use. Therefore, standardization organizations such as the European Committee for Standardization (CEN), the International Organization for Standardization (ISO), and the International Electrotechnical Commission (IEC) as well as industrial stakeholders, European Medicine Agency (EMA), and the nanosafety community responsible for guidelines for nanomaterial (NM) regulation like the Organisation for Economic Co-operation and Development (OECD) have expressed needs for standardized methodologies to measure NP surface chemical properties.
Despite these needs, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Specifically, validated quantitative procedures for the measurement of thickness and composition of nanoparticle coatings and other surface functionalities are needed. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required. These needs have been addressed by us in two interlaboratory comparisons, that will be presented. In addition, the European metrology project SMURFnano will be briefly presented involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs.
T2 - NanoCarbon Annual Conference 2025
CY - Würzburg, Germany
DA - 18.03.2025
KW - Nano
KW - Particle
KW - Silica
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - QNMR
KW - Validation
KW - Potentiometry
KW - XPS
PY - 2025
AN - OPUS4-62790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brinkmann, A.
T1 - A qNMR Method for Quantification of Surface Functional Groups on Silica Nanoparticles: Bilateral Comparisons
N2 - Nanomaterials (NM) of different size, shape, morphology, composition, and surface chemistry are used in a wide range of applications, including medical diagnostics, and imaging and consumer products. The importance of an adequate and reliable characterization is crucial for quality control during NM production, for ensuring an optimum function for the desired application, and for risk assessment studies. Currently there is a lack of reliable and validated methods and reference materials for quantifying NM surface functional groups, despite the importance of surface chemistry for the production of colloidally stable materials, further processing steps, and the interaction with the environment and biological species.
Following our initial study on the use of qNMR for quantifying the amount of amino groups on surface modified silica (1), we have carried out two bilateral comparisons between NRC and BAM to further develop and optimize a reliable protocol for these measurements (2,3), using aminated silica nanoparticles prepared by multiple methods, both commercial and in-house synthesized, and with varying amine content. Solution qNMR is based on dissolving aminated silica nanoparticles in strong base to release the surface grafted amino silane molecules, followed by the quantification of these molecules by solution qNMR using an internal standard. This method provides the amount of total amino groups present in the sample, which can differ from probe accessible or surface-sensitive measurements performed with X-Ray photoelectron spectroscopy (XPS). Complementary measurements using optical assays, involving a labeling step with a dye reporter, and XPS are employed to assess the probe accessible and surface amine content for representative samples. These measurements, which illustrate the advantages and potential limitations of the different characterization methods, will contribute to establish a basis for testing the protocol in an international inter-laboratory comparison and for standardization at ISO Technical Committee 229 – Nanotechnologies.
T2 - BERM
CY - Halifax, Canada
DA - 01.06.2025
KW - Quality assurance
KW - Nano
KW - Particle
KW - Synthesis
KW - Advanced materials
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Surface
KW - qNMR
KW - Optical assay
KW - Interlaboratory comparison
KW - Metrology
KW - Standardization
PY - 2025
AN - OPUS4-63527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
A1 - Abram, Sarah-Luise
A1 - Homann, Christian
A1 - Scholtz, Lena
A1 - Radnik, Jörg
A1 - Resch-Genger, Ute
T1 - Validated and standardized measurements and quantification of surface functionalities on nanoparticles
N2 - Surface-functionalized organic and inorganic engineered nanomaterials (NMs) are widely applied in the life and materials sciences. NM performance depends on key factors such as particle size and shape, crystal phase, morphology, chemical composition, and surface chemistry, i.e., surface coatings, functional groups (FGs), and ligands.1 The latter controls their processability and interaction with the environment and largely their possible toxicity. Thus, methods for FG quantification are important tools for quality control of NM production processes and can foster the sustainable development of functional and safe(r) NMs. This underlines the importance of validated and standardized analytical methods for surface analysis and reference materials.2 This encouraged us to explore simple and versatile tools for quantifying common bioanalytically relevant FGs such as optical assays, electrochemical titration methods, quantitative nuclear magnetic resonance spectroscopy (qNMR), and X-Ray photoelectron spectroscopy (XPS) and to perform a first interlaboratory comparison (ILC) on surface FG quantification.3,4 In a follow-up ILC, BAM and NRC explored qNMR sample preparation, measurement, and data evaluation protocols for commercial and custom-made aminated SiO2 NPs with sizes of 20-100 nm, different amounts of surface amino FGs, and different porosity.5,6 First, the number of amino FGs accessible for a dye reporter was determined with a cost-efficient, automated optical fluorescamine assay. Then, qNMR workflows and protocols were stepwise fine-tuned. The qNMR ILC was complemented by joint XPS measurements. BAM also examined the applicability of fast and automatable potentiometric titrations to screen the total amount of (de)protonable FGs on aminated SiO2 NPs. Our results underline the need to evaluate protocols for FG quantification in ILCs and the advantages of multi-method characterization strategies for efficient method cross validation.
T2 - Surface and Micro/Nano Analysis Working Group
CY - Paris, France
DA - 08.04.2025
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nano
KW - Particle
KW - Surface analysis
KW - XPS
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - QNMR
KW - Potentiometry
PY - 2025
AN - OPUS4-62969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portesi, C.
T1 - qNMR for standardised measurements of surface functionalities on nanoparticles
N2 - Engineered nanoparticles have a large application potential in fields such as medicine, sensing, catalysis, energy storage, and opto-electronics [1]. The applicability and performance of engineered nanoparticles is largely determined by their surface chemistry, i.e. functional groups and ligands on the particle surface. However, documented standards to quantify functional groups and ligands currently do not exist. Such standards are required to support quality control of nanomaterial production and surface modification processes, and safe-by-design concepts and to meet regulatory requirements.
Here, this issue is addressed by developing and standardizing quantitative Nuclear Magnetic Resonance (qNMR) methods for the characterization of surface functionalized nanoparticles which specifically address the determination of the amount and chemical composition of surface functionalities and coatings.
This work is being developed under the EMP project 23NRM02 SMURFnano - Standardised measurements of surface functionalities on nanoparticles. qNMR competence of 7 qNMR laboratories involved in the project was first tested with a molecular model sample i.e. citrate, to be assessed in terms of purity. Citrate is often used as hydrophilic surface ligand for different nanoparticles. Then, the first nanoparticle samples, here a set of aminated SiO2 NPs [1] with a particle size of 100 nm and two amino group densities, prepared and characterized by BAM regarding size and surface charge as well as stability over 21 months with an optical assay and qNMR, were assessed in an international interlaboratory comparison (ILC) on qNMR. Thereby, the amount of surface amino groups introduced by grafting of the silica cores with different amounts of 3-aminopropyl)triethoxysilane (APTES) was quantified by each participant following a sample preparation protocol previously developed by BAM and NRC.The results of the ILC were then used to refine the protocol for sample preparation and to identify critical points for qNMR measurement and data analysis.
This work will contribute to the development of a Preliminary Work Item (PWI) 19257 (ISO/TC 229) on surface functional groups and coatings on nano-objects. Also, it will lay the groundwork to perform ILCs on the quantification and determination of the amount of surface functional groups under the roof of VAMAS TWA2 (Surface Chemical Analysis) for different types of nanomaterials possessing industry-relevant surface functionalities using qNMR. These ILCs will be complemented by other techniques like X-Ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS).
T2 - BERM
CY - Halifax, Canada
DA - 01.06.2025
KW - Quality assurance
KW - Nano
KW - Particle
KW - Synthesis
KW - Advanced materials
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Surface
KW - qNMR
KW - Optical assay
KW - Interlaboratory comparison
KW - Metrology
KW - Validation
KW - Standardization
PY - 2025
AN - OPUS4-63443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Quantifying the total and accessible amount of surface functionalities and ligands on nano-materials: Overview and recommended methods
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. This calls for reliable, reproducible, and standardized surface characterization methods, which are vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Validated and standardized workflows for surface analysis are also increasingly requested by industry, international standardization organizations, regulatory agencies, and policymakers. To establish comparable measurements of surface functionalities across different labs and ease instrument performance validation, reference test materials and reference materials of known surface chemistry as well as reference data are needed.
In the following, different methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques are presented and discussed regarding method-inherent advantages and limitations. Special emphasis is dedicated to traceable quantitative nuclear magnetic resonance (qNMR), X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods.
T2 - LNE Workshop
CY - Paris, France
DA - 04.11.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
AN - OPUS4-64726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardized Measurements of Surface - Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, optoelectronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required and well characterized test and reference nanomaterials providing benchmark values.[1] These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - eMRS
CY - Strasbourg, France
DA - 27.05.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Silica
KW - Upconversion nanoparticles
KW - Optical assay
KW - qNMR
KW - Surface analysis
KW - Ligand
KW - Quantification
KW - Functional group
KW - XPS
KW - ToF-SIMS
KW - Polymer particle
KW - Surface modification
KW - Potentiometry
KW - Metrology
KW - Method
KW - Validation
KW - ILC
PY - 2025
AN - OPUS4-63339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardized Measurements of Surface Functionalities on Nanoparticles - F. Synthesis and characterization of functional nanocomposite materials
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely and commonly fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, their interaction with biological species, and also their environmental fate are largely determined by the surface functionalities of the particles. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, determination of their applicability, and mandatory to meet increasing concerns regarding their safety. In addition, industry as well as international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized up until now. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR), as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter, typically less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required to provide well characterized test and reference nanomaterials including benchmark values.[1] These needs are addressed by the current European metrology project SMURFnano, involving 12 partners from different National Metrology Institutes, designated and research institutes, two university groups as well as one large company and one SME producing NPs. This project, as well as first results derived from the development of test and reference materials with a well characterized surface chemistry, and ongoing interlaboratory comparisons, will be presented.
T2 - Shift 2025
CY - La Laguna, Tenerife
DA - 13.10.2025
KW - Nano
KW - Particle
KW - Silica
KW - Iron oxide
KW - Lanthanide
KW - Metrology
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - qNMR
KW - Validation
KW - Potentiometry
KW - XPS
KW - ILC
KW - Standardization
PY - 2025
AN - OPUS4-64370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Fe2O3 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Fe2O3 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Fe2O3 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941001
PB - Zenodo
CY - Geneva
AN - OPUS4-57665
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, M.
A1 - Schlaich, C.
A1 - Zhang, J.
A1 - Donskyi, Ievgen
A1 - Schwibbert, Karin
A1 - Schreiber, Frank
A1 - Xia, Y.
A1 - Radnik, Jörg
A1 - Schwerdtle, T.
A1 - Haag, R.
T1 - Mussel-inspired multifunctional coating for bacterial infection prevention and osteogenic induction
N2 - Bacterial infection and osteogenic integration are the two main problems that cause severe complications after surgeries. In this study, the antibacterial and osteogenic properties were simultaneously introduced in biomaterials, where copper nanoparticles (CuNPs) were generated by in situ reductions of Cu ions into a mussel-inspired hyperbranched polyglycerol (MI-hPG) coating via a simple dip-coating method. This hyperbranched polyglycerol with 10 % catechol groups’ modification presents excellent antifouling property, which could effectively reduce bacteria adhesion on the surface. In this work, polycaprolactone (PCL) electrospun fiber membrane was selected as the substrate, which is commonly used in biomedical implants in bone regeneration and cardiovascular stents because of its good biocompatibility and easy post-modification. The as-fabricated CuNPs-incorporated PCL membrane [PCL-(MI-hPG)-CuNPs] was confirmed with effective antibacterial performance via in vitro antibacterial tests against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and multi-resistant E. coli. In addition, the in vitro results demonstrated that osteogenic property of PCL-(MI-hPG)-CuNPs was realized by upregulating the osteoblast-related gene expressions and protein activity. This study shows that antibacterial and osteogenic properties can be balanced in a surface coating by introducing CuNPs.
KW - Mussel-inspired coating
KW - CuNPs
KW - Multi-resistant bacteria
KW - Antibacterial
KW - Antifouling
KW - Osteogenesis
PY - 2021
DO - https://doi.org/10.1016/j.jmst.2020.08.011
SN - 1005-0302
VL - 68
SP - 160
EP - 171
PB - Elsevier Ltd.
AN - OPUS4-51519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arinchtein, A.
A1 - Schnack, R.
A1 - Kraffert, K.
A1 - Radnik, Jörg
A1 - Dietrich, P.
A1 - Sachse, René
A1 - Krähnert, R.
T1 - Role of Water in Phase Transformations and Crystallization of Ferrihydrite and Hematite
N2 - The oxides, hydroxides, and oxo-hydroxides of iron belong to the most abundant materials on earth. They also feature a wide range of practical applications. In many environments, they can undergo facile phase transformations and crystallization processes.
Water appears to play a critical role in many of these processes. Despite numerous attempts, the role of water has not been fully revealed yet. We present a new approach to study the influence of water in the crystallization and phase transformations of iron oxides.
The approach employs model-type iron oxide films that comprise a defined homogeneous nanostructure. The films are exposed to air containing different amounts of water reaching up to pressures of 10 bar. Ex situ analysis via scanning electron microscopy, Transmission electron microscopy, selected area electron diffraction, and X-ray diffraction is combined with operando near-ambient pressure X-ray photoelectron spectroscopy to follow water-induced changes in hematite nd ferrihydrite. Water proves to be critical for the nucleation of ematite domains in ferrihydrite, the resulting crystallite orientation, and the underlying crystallization mechanism.
KW - Iron oxide
KW - Ferrihydrite
KW - Hematite
KW - Water
KW - NAP-XPS
KW - High pressure
PY - 2020
DO - https://doi.org/10.1021/acsami.0c05253
VL - 12
SP - 38714
EP - 38722
PB - ACS Publication
AN - OPUS4-51201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stockmann, Jörg M.
T1 - Reference material for the determination of the field of view of small-area X-ray photoelectron spectrometers
N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces. For evaluating the quality of such microstructures, it is crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. The aperture has a major influence on the signal-contribution from the outside. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize the FoV: The signal-contribution from the outside is reduceable down to lower than 50 %, when the aperture is 30 % of the structure dimension for our Kratos AXIS Ultra DLD system.
T2 - Kratos User's Meeting 2020
CY - Online meeting
DA - 21.09.2020
KW - Small-area XPS
KW - Field of View
KW - Imaging XPS
KW - Reference Material
PY - 2020
AN - OPUS4-51412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - Just a minute: X-ray scattering
N2 - An extremely brief summary of what X-ray scattering can do for you (X-ray scattering encompasses small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS/XRD), amongst others). See my other videos for more detailed explanations on sample selection, data correction, data analysis, etc.
KW - X-ray scattering
KW - Introduction
KW - Materials science
KW - Nanostructure investigation
KW - MOUSE
PY - 2022
UR - https://www.youtube.com/watch?v=jWWNQyaCTHA
DO - https://doi.org/10.26272/opus4-55768
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-55768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guitton-Spassky, Tiffany
A1 - Schade, Boris
A1 - Zoister, Christian
A1 - Veronese, Eleonora
A1 - Rosati, Marta
A1 - Baldelli Bombelli, Francesca
A1 - Cavallo, Gabriella
A1 - Thünemann, Andreas
A1 - Ghermezcheshme, Hassan
A1 - Makki, Hesam
A1 - Netz, Roland R.
A1 - Ludwig, Kai
A1 - Metrangolo, Pierangelo
A1 - Singh, Abhishek Kumar
A1 - Haag, Rainer
T1 - Fluorinated Hexosome Carriers for Enhanced Solubility of Drugs
N2 - Designing nanomaterials for drug encapsulation is a crucial, yet challenging, aspect for pharmaceutical development. An important step is synthesizing amphiphiles that form stable supramolecular systems for efficient drug loading. In the case of fluorinated drugs, these have superior properties and also a tendency toward reduced water solubility. For the first time, we report here fluorinated hexosome carriers made from nonionic dendritic amphiphiles, capable of encapsulating the fluorinated drug Leflunomide with high efficiency (62 ± 3%) and increasing its solubility by 12-fold. We synthesized amphiphiles with varying tail groups (fluorinated/alkylated), and their supramolecular self-assembly was investigated using cryogenic transmission electron microscopy and small-angle X-ray scattering. Furthermore, Leflunomide and its equivalent nonfluorinated counterpart were encapsulated within fluorinated and nonfluorinated assemblies. Self-assembly and encapsulation mechanisms were well supported by coarse-grained molecular simulations, yielding a fundamental understanding of the new systems.
KW - PEFAS
KW - Small-angle X-ray scattering
KW - SAXS
KW - Reference method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632002
DO - https://doi.org/10.1021/jacsau.5c00198
SN - 2691-3704
VL - 5
IS - 5
SP - 2223
EP - 2236
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Qiang
A1 - Heuchel, Matthias
A1 - Thünemann, Andreas
A1 - Machatscheck, Rainhard
T1 - The role of diffusion in the hydrolytic degradation of poly(lactic-co-glycolic acid): A molecular perspective
N2 - This research emphasizes the importance of internal surface erosion as a key factor in the hydrolytic degradation of PLGA (poly(D,L-lactic-co-glycolic acid)) providing an alternative view of the established surface and bulk erosion degradation modes. Using molecular dynamics (MD) simulations, this study reveals the role of water and oligomer diffusion during the degradation of PLGA and highlights the importance of water channels formed as the overall water content increases. We found that these continuous water channels play a crucial role in accelerating the transport of water and the release of degradation products from the polymer matrix, as the diffusion coefficients of water and small oligomers exhibit significant differences spanning 2 to 3 orders of magnitude between the water and polymer phases. Water follows a different diffusion mechanism than polymer fragments. The diffusion rate of the fragments up to a size of octamers was found to be size-dependent and reasonably well approximated by a 1/N behavior, in line with the Rouse model.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - PLGA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621250
DO - https://doi.org/10.1016/j.polymdegradstab.2024.111119
VL - 232
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-62125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Alyna
A1 - Holtzheimer, Lea
A1 - Clarke, Coby
A1 - Thünemann, Andreas
A1 - Taubert, Andreas
T1 - Complex Self-Organization in n-Alkylammonium Sulfobetaine Zwitterions with High Thermal Stabilities and High Expansion Coefficients
N2 - Sulfobetaine zwitterions made from n-alkyl dimethylamines and butanesultone yield a series of n-alkylammonium sulfobetaine zwitterions with complex self-organization behavior. The compounds are thermally quite stable and the length of the alkyl chain directly affects all phase transition temperatures of the compounds: the longer the alkyl chain, the higher the transition temperature. All compounds exhibit lamellar order and the different phases are characterized by a lower temperature orthorhombic and a higher temperature hexagonal in-plane order. The phase transition from the orthorhombic to the hexagonal phase is always associated with an increase of the long period. The phase transition is also associated with a rather high thermal expansion coefficient.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanostructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626276
DO - https://doi.org/10.1021/acs.langmuir.4c02892
SN - 1520-5827
VL - 41
SP - 4422
EP - 4434
PB - American Chemical Society (ACS)
AN - OPUS4-62627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kieserling, Helena
A1 - Sieg, Holger
A1 - Heilscher, Jasmin
A1 - Drusch, Stephan
A1 - Braeuning, Albert
A1 - Thünemann, Andreas
A1 - Rohn, Sascha
T1 - Towards Understanding Particle-Protein Complexes: Physicochemical, Structural, and Cellbiological Characterization of β-Lactoglobulin Interactions with Silica, Polylactic Acid, and Polyethylene Terephthalate Nanoparticles
N2 - Nanoplastic particles and their additives are increasingly present in the food chain, interacting with biomacromolecules with not yet known consequences. A protein corona forms around the particles in these usually complex matrices, primarily with a first contact at surface-active proteins. However, systematic studies on the interactions between the particles and proteins –especially regarding protein affinity and structural changes due to surface properties like polarity – are limited. It is also unclear whether the protein corona can "mask" the particles, mimic protein properties, and induce cytotoxic effects when internalized by mammalian cells. This study aimed at investigating the physicochemical properties of model particle-protein complexes, the structural changes of adsorbed proteins, and their effects on Caco-2 cells. Whey protein β-lactoglobulin (β-Lg) was used as a well-characterized model protein and studied in a mixture with nanoparticles of varying polarity, specifically silica, polylactic acid (PLA), and polyethylene terephthalate (PET). The physicochemical analyses included measurements of the hydrodynamic diameter and the zeta potential, while the protein conformational changes were analyzed using Fourier-transform-infrared spectroscopy (FTIR) and intrinsic fluorescence. Cellular uptake in Caco-2 cells was assessed through flow cytometry, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and cellular impedance was analyzed with xCELLigence® technology. The results indicated that β-Lg had the highest affinity for hydrophilic silica particles, forming silica-β-Lg complexes and large aggregates through electrostatic interactions. The affinity decreased for PLA and was lowest for hydrophobic PET, which formed smaller complexes. Adsorption onto silica caused partial unfolding and refolding of β-Lg. The silica-β-Lg complexes were internalized by Caco-2 cells, impairing cell proliferation. In contrast, PLA- and PET-protein complexes were not internalized, though PLA complexes slightly reduced cell viability. This study enhances our understanding of protein adsorption on nanoparticles and its potential biological effects.
KW - Nanoplastics
KW - Microplastics
KW - Reference materials
KW - Scattering
KW - DLS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630093
DO - https://doi.org/10.1016/j.colsurfb.2025.114702
SN - 1873-4367
VL - 253
SP - 1
EP - 12
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mikhlin, Yuri
A1 - Muzikansky, Anya
A1 - Zysler, Melina
A1 - Thünemann, Andreas
A1 - Zitoun, David
T1 - Emerging electrochemistry of high-concentration colloids: Redox-activity, wide potential window and electrophoretic transport of iron oxide nanoparticles
N2 - High-concentration, steric stabilizer free colloids and particularly their electrochemical behavior remains almost unexplored. Herein, we report on the electrochemistry (cyclic voltammetry, impedance spectroscopy, etc.) of highly concentrated aqueous colloidal dispersion up to 800 g/L of citrate-capped ∼11 nm Fe3-xO4 nanoparticles (NPs) without background electrolyte on glassy carbon electrodes. X-ray photoelectron spectroscopy was applied to analyze the reaction products. Solid-state Fe(II)/Fe(III) conversion was concluded to determine the cathodic and anodic faradaic reactions of the particles, with the currents depending on approximately square root of the concentration. The electrochemical reactions are coupled with the electrophoretic transfer of the negatively charged NPs on toward the anode, with the ohmic-type behavior in the bulk demonstrated by the nearly linear voltametric cathodic curves and frequency-independent impedance above ∼10–100 Hz. Accumulation and clogging of the NPs retards diffusion near anode. Hydrogen and especially oxygen evolution are arrested, and very large oxidation overpotentials result in extraordinary wide, up to 12 V, electrochemical window of water stability. The findings shed light onto basic features of the electrochemistry of high-concentration colloids without added electrolyte and their potential applications in redox flow batteries, electrophoretic deposition and beyond.
KW - Nanoplastics
KW - SAXS
KW - Small-angle X-ray scattering
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644340
DO - https://doi.org/10.1016/j.jcis.2025.139247
SN - 0021-9797
VL - 703
SP - 1
EP - 18
PB - Elsevier Inc.
AN - OPUS4-64434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Moschner, J.
A1 - Mikolajczak, D. J.
A1 - Becker, M.
A1 - Thünemann, Andreas
A1 - Kästner, Claudia
A1 - Klemczak, D.
A1 - Stegemann, A.-K.
A1 - Böttcher, C.
A1 - Metrangolo, P.
A1 - Netz, R. R.
A1 - Koksch, B.
T1 - The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation
N2 - The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Nanostructure
KW - Peptide
KW - Amyloid
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518632
DO - https://doi.org/10.1002/cbic.202000373
VL - 21
IS - 24
SP - 3544
EP - 3554
PB - Wiley
CY - Weinheim
AN - OPUS4-51863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liebig, F.
A1 - Sarhan, R. M.
A1 - Schmitt, C. N. Z.
A1 - Thünemann, Andreas
A1 - Prietzel, C.
A1 - Bargheer, M.
A1 - Koetz, J.
T1 - Gold Nanotriangles with Crumble Topping and their Influence on Catalysis and Surface‐Enhanced Raman Spectroscopy
N2 - By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)‐stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5±1 nm and an edge length of about 175±17 nm, the AOT bilayer is replaced by a polymeric HA‐layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA‐shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon‐driven dimerization of 4‐nitrothiophenol (4‐NTP) to 4,4′‐dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
KW - Gold
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503977
DO - https://doi.org/10.1002/cplu.201900745
VL - 85
IS - 3
SP - 519
EP - 526
PB - Wiley-VCH Verlag
CY - Weinheim
AN - OPUS4-50397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Smales, Glen Jacob
A1 - Clark, Adam H.
A1 - Thünemann, Andreas
T1 - Zinc Phosphate Nanoparticles Produced in Saliva
N2 - This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization.
KW - SAXS
KW - Digestion
KW - Zinc phosphate
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514239
DO - https://doi.org/10.1002/ejic.202000521
IS - 38
SP - 3654
EP - 3661
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Schmidt, R. F.
A1 - Sahoo, A. K.
A1 - tom Dieck, T.
A1 - Hohmann, T.
A1 - Schade, B.
A1 - Brademann-Jock, Kerstin
A1 - Thünemann, Andreas
A1 - Netz, R. R.
A1 - Gradzielski, M.
A1 - Koksch, B.
T1 - Rational design of amphiphilic fluorinated peptides: Evaluation of self-assembly properties and hydrogel formation
N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Amyloid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504
DO - https://doi.org/10.1039/D2NR01648F
SN - 2040-3364
VL - 14
IS - 28
SP - 10176
EP - 10189
PB - Royal Society of Chemistry
AN - OPUS4-55350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Yokosawa, T.
A1 - Spiecker, E.
A1 - Klinger, D.
T1 - Regioselective Seeded Polymerization in Block Copolymer Nanoparticles: Post-Assembly Control of Colloidal Features
N2 - Post-assembly modifications are efficient tools to adjust colloidal features of block copolymer (BCP) particles. However, existing methods often address particle shape, morphology, and chemical functionality individually. For simultaneous control, we transferred the concept of seeded polymerization to phase separated BCP particles. Key to our approach is the regioselective polymerization of (functional) monomers inside specific BCP domains. This was demonstrated in striped PS-b-P2VP ellipsoids. Here, polymerization of styrene preferably occurs in PS domains and increases PS lamellar thickness up to 5-fold. The resulting asymmetric lamellar morphology also changes the particle shape, i.e., increases the aspect ratio. Using 4-vinylbenzyl azide as co-monomer, azides as chemical functionalities can be added selectively to the PS domains. Overall, our simple and versatile method gives access to various multifunctional BCP colloids from a single batch of pre-formed particles.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Polymer
KW - Nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557246
DO - https://doi.org/10.1002/anie.202208084
SN - 1433-7851
VL - 61
IS - 35
SP - 1
EP - 11
PB - Wiley
CY - Weinheim
AN - OPUS4-55724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, M. B.
A1 - Fahrenson, C.
A1 - Givelet, L.
A1 - Herrmann, T.
A1 - Loescher, K.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
A1 - Sieg, H.
T1 - Beyond microplastics ‑ investigation on health impacts of submicron and nanoplastic particles after oral uptake in vitro
N2 - The continuously increasing use of plastics is supposed to result in a rising exposure of MNPs to humans. Available data on human health risks of microplastics after oral uptake increased immensely in the past years and indicates very likely only low risks after oral consumption. Concerning nanoplastics, uptake, transport and potential adverse effects after oral uptake are less well understood. This study aims to investigate differences between microplastic particles and particles in the submicron- and nanoscaled size derived from food-relevant polymers with a particle size range consistent with higher potential for cellular uptake, fate, and effects when applied to human intestinal and liver cells. This work includes the development of cellular and subcellular detection methods for synthetic polymeric particles in the micro- and nanometer-range, using Scanning Electron Microscopy, Small-Angle X-ray and Dynamic Light Scattering methods, Asymmetric Flow Field Flow Fractionation, octanol-water fractionation, fluorescence microscopy and flow cytometry. Polylactic acid (250 nm and 2 μm (polydisperse)), melamine formaldehyde (366 nm) and polymethylmethacrylate (25 nm) were thoroughly characterized. The submicro- and nanoplastic test particles showed an increased uptake and transport quantity through intestinal cells. Both types of particles resulted in observed differences of uptake behavior, most likely influenced by different lipophilicity, which varied between the polymeric test materials. Toxic effects were detected after 24 h only in overload situations for the particles in the submicrometer range. This study provides further evidence for gastrointestinal uptake of submicro- and nanoplastics and points towards differences regarding bioavailability between microplastics and smaller plastic particles that may result following the ingestion of contaminated food and beverages. Furthermore, the results reinforce the importance for studying nanoplastics of different materials of varying size, surface properties, polymer composition and hydrophobicity.
KW - Small-angle X-ray scattering
KW - SAXS
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550741
DO - https://doi.org/10.1186/s43591-022-00036-0
VL - 2
SP - 1
EP - 19
PB - Springer Nature
AN - OPUS4-55074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Klinger, D.
T1 - Solvent Annealing of Striped Ellipsoidal Block Copolymer Particles: Reversible Control over Lamellae Asymmetry, Aspect Ratio, and Particle Surface
N2 - Solvent annealing is a versatile tool to adjust the shape and morphology of block copolymer (BCP) particles. During this process, polar solvents are often used for block-selective swelling. However, such water-miscible solvents can induce (partial) solubilization of one block in the surrounding aqueous medium, thus, causing complex structural variations and even particle disassembly. To reduce the complexity in morphology control, we focused on toluene as a nonpolar polystyrene-selective solvent for the annealing of striped polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) ellipsoids. The selective stretching of PS chains produces unique asymmetric lamellae structures, which translate to an increase in the particle aspect ratio after toluene evaporation. Complete reversibility is achieved by changing to chloroform as a nonselective solvent. Moreover, surfactants can be used to tune block-selective wetting of the particle surface during the annealing; for example, a PS shell can protect the internal lamellae structure from disassembly. Overall, this versatile postassembly process enables the tailoring of the structural features of striped colloidal ellipsoids by only using commercial BCPs and solvents.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Polymer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543731
DO - https://doi.org/10.1021/acsmacrolett.1c00665
VL - 11
IS - 3
SP - 319
EP - 335
PB - American Chemical Society
AN - OPUS4-54373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, L.
A1 - Hoche, E.
A1 - Stock, V.
A1 - Böhmert, L.
A1 - Braeuning, A.
A1 - Thünemann, Andreas
A1 - Sieg, H.
T1 - Intestinal and hepatic effects of iron oxide nanoparticles
N2 - Iron oxide nanoparticles gain increasing attention due to their broad industrial use. However, safety concerns exist since their effects on human cells are still under investigation. The presence of iron oxide nanoparticles in the food pigment E172 has been shown recently. Here, we studied four iron oxide nanoparticles, one food pigment E172 and the ionic control FeSO4 regarding dissolution in biological media, uptake and transport, and cellular effects in vitro in human intestinal Caco-2 and HepaRG hepatocarcinoma cells. The iron oxide nanoparticles passed the gastrointestinal passage without dissolution and reached the intestine in the form of particles. Minor uptake was seen into Caco-2 cells but almost no transport to the basolateral site was detected for any of the tested particles. HepaRG cells showed higher particle uptake. Caco-2 cells showed no alterations in reactive oxygen species production, apoptosis, or mitochondrial membrane potential, whereas two particles induced apoptosis in HepaRG cells, and one altered mitochondrial membrane potential at non-cytotoxic concentrations. No correlation between physicochemical particle characteristics and cellular effects was observed, thus emphasizing the Need for case-by-case assessment of iron oxide nanoparticles.
KW - Nanoparticles
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521651
DO - https://doi.org/10.1007/s00204-020-02960-7
VL - 95
IS - 3
SP - 895
EP - 905
PB - Springer
AN - OPUS4-52165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, J.
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
T1 - Towards automation of the polyol process for the synthesis of silver nanoparticles
N2 - Metal nanoparticles have a substantial impact across diferent felds of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize silver nanoparticles often do not result in well-defned products, the main obstacles being high polydispersity or a lack of particle size tunability. We describe an automated approach to on-demand synthesis of adjustable particles with mean radii of 3 and 5 nm using the polyol route. The polyol process is a promising route for silver nanoparticles e.g., to be used as reference materials. We characterised the as-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties.
KW - Sillver
KW - Nanoparticles
KW - Automated synthesis
KW - Chemputer
KW - Scattering
KW - SAXS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546803
DO - https://doi.org/10.1038/s41598-022-09774-w
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Springer
AN - OPUS4-54680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Rybak, Tina
A1 - Thünemann, Andreas
T1 - Microwave-Assisted Synthesis of ZnO Nanoparticles: Phase Transfer to Water
N2 - Herein, a simple one-pot procedure is reported to obtain aqueous zinc oxide (ZnO) nanoparticle dispersions from ZnO nanoparticles dispersed in cyclohexane. In the process, polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80) functions as a phase transfer agent and colloidal stabilizer. The particles grow in a defined manner during the transfer, presumably via coalescence. The final particle radii are tuneable in the range from 2.3 ± 0.1 nm to 5.7 ± 0.1 nm depending on the incubation time of the dispersion at 90 °C. Small-angle X-ray scattering is employed to determine the particle radius distributions before and after phase transfer. The larger ZnO particle radii are associated with a redshift of the optical bandgap and luminescence emission, as expected for semiconductor nanoparticles. The particles presented here exhibit a relative size distribution width of 20%, rendering them attractive for applications in, e.g., biology or catalysis. The latter application is demonstrated at the photocatalytic degradation of methylene blue dye.
KW - SAXS
KW - Small-angle X-ray scattering
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551502
DO - https://doi.org/10.1002/adem.202101276
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-55150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Maxi B.
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Loeschner, Katrin
A1 - Givelet, Lucas
A1 - Fahrenson, Christoph
A1 - Braeuning, Albert
A1 - Sieg, Holger
T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics
N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.
KW - Toxicology
KW - Nanoparticles
KW - Dynamic Light Scattering
KW - Nanoplastics
KW - Microplastics
KW - Reference Method
KW - Reference Material
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947
DO - https://doi.org/10.1016/j.fct.2023.114423
SN - 0278-6915
VL - 184
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, Holger
A1 - Schaar, Caroline
A1 - Fouquet, Nicole
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Braeuning, Albert
T1 - Particulate iron oxide food colorants (E 172) during artificial digestion and their uptake and impact on intestinal cells
N2 - Iron oxide of various structures is frequently used as food colorant (E 172). The spectrum of colors ranges from yellow over orange, red, and brown to black, depending on the chemical structure of the material. E 172 is mostly sold as solid powder. Recent studies have demonstrated the presence of nanoscaled particles in E 172 samples, often to a very high extent. This makes it necessary to investigate the fate of these particles after oral uptake. In this study, 7 differently structured commercially available E 172 food colorants (2 x Yellow FeO(OH), 2 x Red Fe2O3, 1 x Orange Fe2O3 + FeO(OH) and 2 x Black Fe3O4) were investigated for particle dissolution, ion release, cellular uptake, crossing of the intestinal barrier and toxicological impact on intestinal cells. Dissolution was analyzed in water, cell culture medium and artificial digestion fluids. Small-angle X-ray scattering (SAXS) was employed for determination of the specific surface area of the colorants in the digestion fluids. Cellular uptake, transport and toxicological effects were studied using human differentiated Caco-2 cells as an in vitro model of the intestinal barrier. For all materials, a strong interaction with the intestinal cells was observed, albeit there was only a limited dissolution, and no toxic in vitro effects on human cells were recorded.
KW - Toxicology
KW - Nanoparticles
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593935
DO - https://doi.org/10.1016/j.tiv.2024.105772
VL - 96
SP - 1
EP - 12
PB - Elsevier BV
AN - OPUS4-59393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Annadurai, V.
A1 - Balazs, D. M.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Del Giudice, A.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Garcia, P. R. A. F.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, M.
A1 - Hollamby, M.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Rochels, L.
A1 - Rosalie, Julian
A1 - Saloga, Patrick E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz M.
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round Robin
KW - Data analysis
KW - Small-angle scattering
KW - Nanomaterials
KW - Interlaboratory comparability
KW - Nanostructure quantification
KW - Methodology
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587091
DO - https://doi.org/10.1107/S1600576723008324
SN - 1600-5767
VL - 56
IS - 6
SP - 1618
EP - 1629
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Taubert, Andreas
A1 - Thünemann, Andreas
T1 - Synthesis and Characterization of Ultra‐Small Gold Nanoparticles in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Dicyanamide, [Emim][DCA]
N2 - AbstractWe report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long‐term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2O) with the ionic liquid 1‐ethyl‐3‐methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small‐angle X‐ray scattering (SAXS), UV‐Vis spectroscopy, and MALDI‐TOF mass spectrometry. A three‐stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz‐Slyozov‐Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters.
KW - Reference materials
KW - SAXS
KW - Gold
KW - Nanoparticle
KW - Small-angle X-ray scattering
KW - Ionic liquid
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588203
DO - https://doi.org/10.1002/open.202300106
SN - 2191-1363
VL - 44
SP - 1
EP - 19
PB - Wiley
AN - OPUS4-58820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Thünemann, Andreas
T1 - Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics
N2 - Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D h = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of 𝜻 = −43 ± 2 mV.
KW - Nanoparticles
KW - Reference Material
KW - Nanoplastics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571799
DO - https://doi.org/10.1002/marc.202200874
SN - 1022-1336
VL - 44
IS - 6
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Balazs, D. M.
A1 - Beyer, F. L.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Giudice, A. D.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, Max
A1 - Hollamby, M. J.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Ricardo de Abreu Furtado Garcia, P.
A1 - Rochels, L.
A1 - Rosalie, Julian
A1 - Saloga, P. E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Annadurai, V.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A Round Robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions, and two from powders.
Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5 % and half of the population width entries within 40 %, respectively. Due to the added complexity of the structure factor, much fewer people submitted answers on the powder datasets.
For those that did, half of the entries for the means and widths were within 44 % and 86 % respectively. This Round Robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round robin
KW - Sall-angle scattering
KW - Nanostructure quantification
KW - Nanostructure
KW - SAXS
KW - MOUSE
KW - X-ray scattering
KW - Size distribution
KW - Nanoparticles
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571342
DO - https://doi.org/10.48550/arXiv.2303.03772
SP - 1
EP - 23
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-57134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - STOP and Scatter
N2 - We present first X-ray scattering results for the Horizon Europe project "Surface Transfer of Pathogens" (STOP) and an outlook regarding X-ray scattering methods on thin films, which are under development at the MOUSE.
T2 - M17 full project meeting - Surface Transfer of Pathogens (STOP)
CY - EMPA, St. Gallen, Switzerland
DA - 18.01.2024
KW - X-ray Scattering
KW - Grazing incidence
PY - 2024
AN - OPUS4-62723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - Next Level Grazing Incidence: Let the Standardization Begin
N2 - Reproducibility of experiments is something most natural scientists would consider important. However, how do we know experiments are comparable between instruments without explicitly disclosing, tracking and discussing instrument calibration and data processing methods? At SXNS17 we would like to introduce our standardization initiative to the Grazing Incidence Small-Angle Scattering (GISAS) community and gather initial feedback and perhaps contributors before we proceed further.
From the point of view of development of a new lab GISAXS setup at BAM (Berlin, Germany), we propose a draft autoalignment and calibration routine. Together with the GISAS community, we would like to further develop this routine into a standard. On that basis, agreed-upon methods for data treatment could be the next step for the future and perhaps an organization like the Open Reflectometry Standards Organisation .
We begin with a survey of hardware in use around the world, an area we are not planning to address in terms of standardization but which nonetheless provides the practical background for our efforts. We assume availability of pitch, roll, y and z motions, those may be present in the form of a stack of stages, a hexapod, or even a robot arm. All of these can be used for GISAS, but specifications such as backlash direction and minimum incremental motion need to be considered when it comes to resolution and repeatability of experiments. We ask for your help in gathering information on sample stages and holders and would like to present the results at the International Small-Angle Scattering Conference (SAS2024) in November 2024. We believe this an important step to ensure any developed standard can work for everyone in the end.
Inspired by work for Grazing Incidence X-ray Diffraction one of our goals is to estimate and propagate uncertainties from stage motions to scattering vector q (compare for Small-Angle X-ray Scattering). Further ideas for standardization include the use of reflectometry in choosing angles of incidence and, perhaps more importantly, data corrections.
T2 - Surface X-ray and Neutron Scattering 17 (SXNS17)
CY - EPN, Grenoble, France
DA - 15.07.2024
KW - Grazing incidence scattering
KW - Sample alignment
KW - Community survey
KW - Calibration
PY - 2024
AN - OPUS4-62724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hewel, M.
A1 - Siemann, U.
A1 - Smarsly, B.
A1 - Stribeck, A.
A1 - Thünemann, Andreas
T1 - Nachruf auf Wilhelm Ruland
N2 - Mit Prof. Dr. Wilhelm Ruland starb am 3. Februar 2021 einer der letzten großen Wissenschaftler, welche die Streutheorie nach dem Zweiten Weltkrieg vorangetrieben haben. Sein zentrales Thema war die Streuung an weicher Materie. Hier lieferte er bis ins hohe Alter grundlegende Beiträge, die den Stellenwert seines Leitspruchs demonstrieren: Nichts ist praktischer als eine gute Theorie.
KW - SAXS
PY - 2021
VL - 20
IS - 4
SP - 50
EP - 50
PB - Wiley
AN - OPUS4-52413
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - SAXS for the development of reference materials: Silver nanoparticles, a case study
N2 - Today there are hundreds of products available containing silver in form of nanoparticles, so-called nanosilver. This situation and the foreseeable future growing market of nanosilver will supposedly cause an increased release of silver into the environment. In this way, silver can be also incorporated into the human body and accumulated in different organs, which can be toxic or at least an unknown risk to human health. For these reasons, it is important to constantly study materials containing silver nanoparticles, their production, application in products and technical processes, dissemination of silver nanoparticles in the environment, and effects on humans and nature. The state-of-the-art nanoparticle size and concentration characterization are illustrated in an extensive interlaboratory comparison. To guarantee the traceability of measurements and to secure the comparison of results of different analytical methods, reference materials (RM) and certified reference materials (CRM) are essential. As a case study, the objective of the presented project was to provide an aqueous suspension of silver nanoparticles as a reference material with a nominal diameter below 10 nm for application in the determination of the size and concentration of nanoparticles in an aqueous surrounding. Measurands are the particles’ diameter D, size distribution width σ, number density N, and concentration c. Target uncertainties, defined as one sigma of the measurand values, are 5% for D, 10% for σ, 20% for N, and 20% for c. The certification was carried out based on ISO 17867 and the relevant ISO-Guides to produce reference material. The process of using SAXS as a reliable method for testing homogeneity and short-term and long-term stability of the material is reported. The particle preparation is described in detail so that the user can carry out the steps of synthesis and characterization in his own laboratory if required. Optionally, one can also contact the author for the provision of the silver nanoparticles. Detailed information can be found elsewhere (BAM Certification Reports, BAM-N008 (2022)).
T2 - SAXS excites
CY - Graz, Austria
DA - 04.04.2023
KW - Nanoparticles
KW - SAXS
KW - Nanosilver
KW - Small-angle x-ray scattering
PY - 2023
AN - OPUS4-57283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous Dispersions of polypropylene as possible reference material for nanoplastics
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastics are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a "methodological gap" in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nanoplastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastics found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics such as polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). Nano-PP was formed via a top-down method where the polymer was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks.
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). The chemical analysis of the nanoplastics was performed via Fourier Transform Infrared spectroscopy. To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
T2 - European Polymer Congress 2022
CY - Prag, Czechia
DA - 26.06.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, H.
A1 - Klusmann, L.
A1 - Ellermann, A. L.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
T1 - Counterions determine uptake and effects of aluminum in human intestinal and liver cells
N2 - Aluminum (Al) is highly abundant in the biosphere and can occur in different physico-chemical states. It is present in human food and undergoes transitions between dissolved and particulate species during the passage of the gastrointestinal tract. Moreover, in a complex matrix such as food different inorganic and organic counterions can affect the chemical behavior of Al following oral uptake.
In this work, the effects of different counterions, namely chloride, citrate, sulfate, lactate and acetylacetonate, on Al uptake and toxicity in the human intestine are studied. The respective Al salts showed different dissolution behavior in biological media and formed nanoscaled particles correlating in reverse with the amount of their dissolved fraction. The passage through the intestinal barrier was studied using a Caco-2 Transwell® system, showing counterion-dependent variance in cellular uptake and transport. In addition, Al toxicity was investigated using Al species (Al3+, metallic Al0 and oxidic γAl2O3 nanoparticles) and counterions individually or in mixtures on Caco-2 and HepG2 cells. The strongest toxicity was observed using a combination of Al species, depending on solubility, and the lipophilic counterion acetylacetonate. Notably, only the combination of both led to toxicity, while both substances individually did not show toxic effects. A toxification of previously non-toxic Al-species by the presence of acetylacetonate is shown here for the first time. The dependency on the concentration of free Al ions was demonstrated using sodium hydrogen phosphate, which was able to counteract the toxic effects by complexing free Al ions.
These findings, using Al salts as an example for a common food contaminant, underline the importance of a consideration of the chemical properties of human nutrition, especially dissolution and hydrophobicity, which can significantly influence the cellular uptake and effects of xenobiotic substances.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2022
DO - https://doi.org/10.1016/j.tiv.2021.105295
VL - 79
SP - 1
EP - 7
PB - Elsevier
AN - OPUS4-54110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, A.
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L. J.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment.
The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - Lanthanides
KW - Structural Analysis
KW - Separation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510821
DO - https://doi.org/10.1002/chem.202002653
SN - 0947-6539
VL - 26
SP - 1
EP - 8
PB - WILEY-VCH Verlag GmbH & co. KGaA
AN - OPUS4-51082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Bogoclu, Can
A1 - Emmerling, Franziska
A1 - Streli, Christina
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach
N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications.
KW - Machine Learning
KW - GE-XANES
KW - Bayesian Optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955
DO - https://doi.org/10.1088/2632-2153/ad4253
VL - 5
IS - 2
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-60395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ihlenburg, R. B. J.
A1 - Mai, T.
A1 - Thünemann, Andreas
A1 - Baerenwald, R.
A1 - Saalwächter, K.
A1 - Koetz, J.
A1 - Taubert, A.
T1 - Sulfobetaine Hydrogels with a Complex Multilength-Scale Hierarchical Structure
N2 - Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N′,N′-tetramethyl-N,N′-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Gel
PY - 2021
DO - https://doi.org/10.1021/acs.jpcb.0c10601
SN - 1520-6106
VL - 125
IS - 13
SP - 3398
EP - 3408
PB - American Chemical Society
AN - OPUS4-52403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - PP Nanoplastics Dispersed In Water As Reference Materials
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastic are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a “methodological gap” in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nano plastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics, starting with polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). PP was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks. The
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
This method is repeatable and well suited to produce reference material, as which we propose our prepared particles, based on a homogeneity study, that we performed, following the ISO Guide 35 for reference materials.
T2 - Prague Meeting on Macromolecules 2022
CY - Prag, Czechia
DA - 24.07.2022
KW - Nanoplastic
KW - Reference material
PY - 2022
AN - OPUS4-55961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous dispersions of polypropylene: towards referencematerials for nanoplastics characterization
N2 - Plastic pollution in the environment is a rising concern for the health of our planet. The plastic litter that pollutes our environment leads to microplastic particles. They can be found (nearly) everywhere. The processes that lead to microplastic can also form nanoplastic particles, which have a size below 1 µm. Because of the small size they can penetrate tissue more easily. Only few risk assessment studies of nanoplastics were carried out so far.
Using polystyrene (PS) nanoparticles to test effects on organisms is easy because it is commercially available. However, this falls a little short, as the polyolefins i.e., polypropylene (PP) and polyethylene (PE), are produced in a larger proportion than PS. Moreover, these plastics are mainly used for disposable products, which means that they also account for a large proportion of plastic waste. Therefore, the percentage of polyolefins in environmental nanoplastic is presumably high. It is important to test the toxicological effects also with nanoplastics made of PP and PE to have more realistic results.
Herein, we present an easy and repeatable method to prepare an aqueous dispersion of polypropylene nanoplastics (nano-PP). They are stabilized electrostatically, resulting in a strongly negative zeta potential of -43 mV (± 2 mV) and making no surfactant necessary to keep the dispersion stable.
The size and the size distribution were determined via Dynamic Light Scattering (DLS) and gives a hydrodynamic diameter of 180.5 nm (± 5.8 nm) and a PDI of 0.084 (± 0.023).
Finally, ca. 480 bottles of the dispersion with a volume of 10 mL each were prepared to serve as a potential reference material for further testing of detection methods or risk assessments.
T2 - International Conference on Microplastic Pollution in the Mediterranean Sea
CY - Neapel, Italy
DA - 25.09.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Polypropylene and polyethylene nanoplastics in water
N2 - Considering the huge amount of plastics, that is produced and thrown away all over the world every day, an increasing part of the society became aware of microplastic and its possible impact on the environment. Polymer particles smaller than 1 µm are called nanoplastic. Due to their small size they form a special group within particulate waste. Their high specific surface makes it easier for them to penetrate tissue and pose potential harm. On the other hand, the size and the chemical structure make it difficult to detect and analyze nanoplastics in nature. Furthermore, the concentrations in environmental samples are very low. Therefore, there is a need for a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
T2 - Tag der Chemie 2021 Uni Potsdam
CY - Online meeting
DA - 06.07.2021
KW - Nanoplastic
PY - 2021
AN - OPUS4-53775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Karafiludis, Stephanos
A1 - Pimentel, Carlos
A1 - Montes-Hernández, German
A1 - Kochovski, Zdravko
A1 - Bienert, Ralf
A1 - Weimann, Karin
A1 - Emmerling, Franziska
A1 - Scoppola, Ernesto
A1 - Van Driessche, Alexander E.S.
T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines
N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios.
KW - Industrial and Manufacturing Engineering
KW - Strategy and Management
KW - General Environmental Science
KW - Renewable Energy, Sustainability and the Environment
KW - Building and Construction
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Scattering
KW - Raman
KW - In situ
KW - Synchrotron
KW - BESSY
KW - MySpot
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594698
UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1
DO - https://doi.org/10.1016/j.jclepro.2024.141012
SN - 0959-6526
VL - 440
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-59469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Gluth, Gregor
A1 - Mittermayr, F.
A1 - Ukrainczyk, N.
A1 - Bertmer, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Leis, A.
A1 - Dietzel, M.
T1 - Deterioration mechanism of alkali-activated materials in sulfuric acid and the influence of Cu: A micro-to-nano structural, elemental and stable isotopic multi-proxy study
N2 - In this study, a multi-proxy approach combining 29Si, 27Al and 1H MAS-NMR, FEG-EPMA, XANES at the Cu K-edge and XRD analytics with hydrochemical tools such as ICP-OES analyses, oxygen-isotope signatures, and thermodynamic modelling was applied to K-silicate-activated metakaolin specimens - with and without CuSO4·5H2O addition - exposed to sulfuric acid at pH = 2 for 35 days. The results revealed a multistage deterioration mechanism governed by (i) acid diffusion, (ii) leaching of K-A-S-H, (iii) microstructural damage related to precipitation of expansive (K,Ca,Al)-sulfate-hydrate phases (iv) complete dissolution of the K-A-S-H framework, (v) and formation of silica gel in the outermost corroded regions. Copper ions were mainly located in layered spertiniite-chrysocolla-like phases in the as-cured materials. The results demonstrate an overall negative effect of Cu addition on chemical material durability, implying that the reported higher durability of Cu-doped AAM in biocorrosion environments can be best explained by bacteriostatic effects.
KW - Alkali-activated materials
KW - Acid resistance
KW - Microbially induced corrosion
KW - MIC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520567
DO - https://doi.org/10.1016/j.cemconres.2021.106373
SN - 0008-8846
VL - 142
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-52056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kulow, Anicó
A1 - Kabelitz, Anke
A1 - Grunewald, C.
A1 - Seidel, R.
A1 - Chapartegui-Arias, Ander
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
A1 - Beyer, S.
T1 - Observation of early ZIF-8 crystallization stages with X-ray absorption spectroscopy
N2 - The present study investigates early stages of ZIF-8 crystallization up to 5 minutes post mixing of precursor solutions. Dispersive X-ray Absorption Spectroscopy (DXAS) provides a refined understanding of the evolution of the coordination environment during ZIF-8 crystallization. Linear Combination Fiting (LCF) suggests tetrakis(1-methylimidazole)zinc2+ to be a suitable and stable mononuclear structure analogue for some early stage ZIF-8 intermediates. Our results pave the way for more detailed studies on physico-chemical aspects of ZIF-8 crystallization to better control tailoring ZIF-8 materials for specific applications.
KW - In-situ
KW - XANES
KW - ZIF-8
KW - Crystallization
PY - 2020
DO - https://doi.org/10.1039/D0SM01356K
SN - 1744-6848
VL - 17
IS - 2
SP - 331
EP - 334
PB - Royal Scociety of Chemistry
AN - OPUS4-51723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Chen, K.
A1 - Radu, F.
A1 - Weschke, E.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
T1 - Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2,3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-Surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.
KW - X-ray magnetic circular dichroism (XMCD)
KW - High-entropy alloys
KW - Reverse Monte Carlo
KW - Magnetism
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530668
DO - https://doi.org/10.1007/s12274-021-3704-5
SN - 1998-0124
VL - 15
IS - 6
SP - 4845
EP - 4858
PB - Springer
AN - OPUS4-53066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Recent developments of X-ray absorption spectroscopy as analytical tool for biological and biomedical applications
N2 - X-ray absorption spectroscopy (XAS), in its various modalities, has gained exponential attention and applicability in the field of biological and biomedical systems. Particularly in this field, challenges like low concentration of analyte or proneness to radiation damage have certainly settle the basis for further analytical developments, when using X-ray based methods. Low concentration calls for higher sensitivity—by increasing the detection limits (DL); while susceptibility for radiation damage requires shorter measurement times and/or cryogenic sample environment possibilities. This manuscript reviews the latest analytical possibilities that make XAS more and more adequate to investigate biological or biomedical systems in the last 5 years.
KW - Biological & biomedical applications
KW - TXRF-XAS
KW - HERFD-XAS
KW - RXES
KW - Quick-XAS
KW - Dispersive-XAS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531206
DO - https://doi.org/10.1002/xrs.3254
SN - 0049-8246
VL - 51
IS - 3
SP - 1
EP - 10
PB - John Wiley & Sons Ltd
AN - OPUS4-53120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, Alevtina
A1 - Gaertner, Daniel
A1 - Kuzmin, Alexei
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schuck, Goetz
A1 - Zizak, Ivo
A1 - Wilde, Gerhard
A1 - Yusenko, Kirill
A1 - Divinski, Sergiy
T1 - Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi high-entropy alloy
N2 - AbstractMulti-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with reverse Monte Carlo (RMC) simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing temperature. Two representative states, namely a high-temperature state, created by annealing at 1373 K, and a low-temperature state, produced by long-term annealing at 993 K, were compared in detail. Specific features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative temperatures. The detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.
KW - Electrical and Electronic Engineering
KW - General Materials Science
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics, and Optics
KW - CCMat
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597687
DO - https://doi.org/10.1007/s12274-024-6443-6
SN - 1998-0124
VL - 17
IS - 6
SP - 5336
EP - 5348
PB - Springer Science and Business Media LLC
AN - OPUS4-59768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Edzards, Joshua
A1 - Saßnick, Holger-Dietrich
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Valencia, Ana M.
A1 - Emmerling, Franziska
A1 - Beyer, Sebastian
A1 - Cocchi, Caterina
T1 - Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks
N2 - Due to their favorable properties and high porosity, zeolitic imidazolate frameworks (ZIFs) have recently received much limelight for key technologies such as energy storage, optoelectronics, sensorics, and catalysis. Despite widespread interest in these materials, fundamental questions regarding the zinc coordination environment remain poorly understood. By focusing on zinc(II)2-methylimidazolate (ZIF-8) and its tetrahedrally coordinated analogues with Br-, Cl-, and H-substitution in the 2-ring position, we aim to clarify how variations in the local environment of Zn impact the charge distribution and the electronic properties of these materials. Our results from densityfunctional theory confirm the presence of a Zn coordinative bond with a large polarization that is quantitatively affected by different substituents on the organic ligand. Moreover, our findings suggest that the variations in the Zn coordination induced by the functionalization have a negligible effect on the electronic structure of the considered compounds. On the other hand, halogen terminations of the ligands lead to distinct electronic contributions in the vicinity of the frontier region which ultimately reduce the band gap size by a few hundred millielectron volts. Experimental results obtained from X-ray absorption spectroscopy (Zn K-edge) confirm the trends predicted by theory and, together with them, contribute to a better understanding of the structure−property relationships that are needed to tailor ZIFs for target applications.
KW - Surfaces
KW - Physical and Theoretical Chemistry
KW - General Energy
KW - Electronic
KW - Coatings and Films
KW - Optical and Magnetic Materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589117
DO - https://doi.org/10.1021/acs.jpcc.3c06054
SN - 1932-7447
VL - 127
IS - 43
SP - 21456
EP - 21464
PB - American Chemical Society (ACS)
AN - OPUS4-58911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunkel, B.
A1 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, S.
T1 - Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling
N2 - The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde.
This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1
KW - Artificial neural network modelling
KW - Selective oxidation
KW - Molecular VOx catalysts
KW - Formaldehyde
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517420
DO - https://doi.org/10.3390/catal10121411
VL - 10
IS - 12
SP - 1411
PB - MDPI
AN - OPUS4-51742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Olivera, Paulo
A1 - Michalchuk, Adam
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Bienert, Ralf
A1 - Torresi, R.
A1 - Camargo, P.
A1 - Emmerling, Franziska
T1 - Tandem X-ray absorption spectroscopy and scattering for in situ time-resolved monitoring of gold nanoparticle mechanosynthesis
N2 - Current time-resolved in situ approaches limit the scope of mechanochemical investigations possible. Here we develop a new, general approach to simultaneously follow the evolution of bulk atomic and electronic structure during a mechanochemical synthesis. This is achieved by coupling two complementary synchrotron-based X-ray methods: X-ray absorption spectroscopy (XAS) and X-ray diffraction. We apply this method to investigate the bottom-up mechanosynthesis of technologically important Au micro and nanoparticles in the presence of three different reducing agents, hydroquinone, sodium citrate, and NaBH4. Moreover, we show how XAS offers new insight into the early stage generation of growth species (e.g. monomers and clusters), which lead to the subsequent formation of nanoparticles. These processes are beyond the detection capabilities of diffraction methods. This combined X-ray approach paves the way to new directions in mechanochemical research of advanced electronic materials.
KW - Mechanochemistry
KW - XANES
KW - X-ray diffraction
KW - Nano particles
PY - 2020
DO - https://doi.org/10.1039/d0cc03862h
SN - 1364-548X
VL - 56
SP - 10329
EP - 10332
PB - Royal Society of Chemistry
AN - OPUS4-51760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, Annika
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - PQQ
KW - Lanthanoide
KW - Coordination chemistry
KW - Rare earth elements separations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707
DO - https://doi.org/10.1002/chem.202002653
VL - 26
IS - 44
SP - 10133
EP - 10139
AN - OPUS4-51270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Taylor, J.
A1 - Thakur, S.
A1 - Radu, F.
A1 - Weschke, E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Xiao, B.
A1 - Savan, A.
A1 - Yusenko, Kirill
A1 - Ludwig, A.
T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale
N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS),
KW - X-ray magnetic circular dichroism (XMCD),
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254
DO - https://doi.org/10.1007/s12274-022-5135-3
SN - 1998-0124
SP - 5626
PB - Springer
AN - OPUS4-57825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Kunkel, Benny
A1 - Cakir, Cafer Tufan
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Bernstein, Thomas
A1 - Bartling, Stephan
A1 - Radtke, Martin
A1 - Emmerling, Franziska
A1 - Abdel-Mageed, Ali Mohamed
A1 - Wohlrab, Sebastian
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy
N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated.
KW - Dispersive XAS
KW - Catalysis
KW - In situ
KW - Structure analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924
DO - https://doi.org/10.1039/d3cc03277a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -