TY - RPRT A1 - Rades, Steffi A1 - Natte, Kishore A1 - Unger, Wolfgang T1 - NanoValid D.5.47 Annex 1, Inter-laboratory comparison on measurand particle size/particle size distribution - Report of the results N2 - An inter-laboratory comparison on the particle size, expressed as mean diameter d, of nanoscaled SiO2 (#14 BAM Silica (see NanoValid DoW, D.5.41/5.42)) has been performed. The majority of participants used Dynamic Light Scattering (DLS). A few used Electron Microscopy as method. Following methods had been applied by only one partner, respectively: Small Angle X-ray Scattering, Analytical Ultracentrifugation, Atomic Force Microscopy and Atomizer with electric mobility spectrometer. KW - Nanoparticle size measurement KW - Silica nanoparticles KW - Inter-laboratory comparison KW - EU FP7 project NanoValid PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488117 DO - https://doi.org/10.5281/zenodo.3380570 SP - 1 EP - 23 PB - Zenodo CY - Geneva AN - OPUS4-48811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Daniel A1 - Resch-Genger, Ute T1 - Development of reference materials (WP1) and reference methods (WP2) for the standardisation of concentration measurements of extracellular vesicles N2 - BAM provides leading expertise in preparation, characterisation and application of fluorescent reference standards and biomedical relevant nanomaterials, as well as in traceable, absolute, and quantitative fluorometric measurements of transparent and scattering systems in the ultraviolet, visible, and near infrared spectral region. BAM will prepare solid low-RI particles in WP1, will develop reference methods to determine the fluorescence intensity and RI of reference materials in WP2, and will measure the fluorescence intensity of EVs in biological test samples of WP3. T2 - EMPIR 18HLT01 "MetVesII" Kick-off meeting CY - Delft, The Netherlands DA - 17.06.2019 KW - Reference materials KW - Reference methods KW - Extracellualr vesicles PY - 2019 AN - OPUS4-48813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Munasir, A1 - Triwikantoro, A1 - Zainuri, M. A1 - Bäßler, Ralph A1 - Darminto, T1 - Corrosion Polarization Behavior of Al-SiO2 Composites in 1M NaCl and Related Microstructural Analysis N2 - The composites combining aluminum and silica nanoparticles with the addition of tetramethylammonium hydroxide (Al-SiO2(T)) and butanol (Al-SiO2(B)) as mixing media have been successfully fabricated. Corrosion behavior of Al-SiO2 composites before and after exposure in 1M NaCl solution was examined using potentiodynamic polarization (Tafel curve analysis). The study was also equipped with scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) investigations. Before exposure, Al-SiO2(T) exhibited the best corrosion resistance. Performance improvement was indicated by Al-SiO2(B) up to 10 times better than Al-SiO2(T) after exposure. The increased SiO2 content did not significantly enhance the corrosion resistance of the composites. The Al-SiO2 composites with 5% SiO2 content showed very high corrosion resistance (as the optimum composition). Furthermore, pitting corrosion was observed in the Al-SiO2 composites, indicated by the formation of corrosion products at grain boundaries. The product was affected by the presence of SiO2 in the Al matrix and the NaCl environment at 90 °C (approach to synthetic geothermal media: Na+, Cl, H+, OH-). Our study revealed the presence of γ-Al2O3, γ-Al(OH)3, and Al(OH)2Cl as the dominant corrosion products. KW - Al-Composite KW - Corrosion KW - Corrosion rate KW - SiO2 Nanoparticle KW - Tafel Plot PY - 2019 DO - https://doi.org/10.5829/ije.2019.32.07a.11 SN - 1025-2495 SN - 1735-9244 VL - 7 IS - 32 SP - 982 EP - 990 PB - Materials and Energy Research Center AN - OPUS4-48742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures: from nanoscaled light localization to applications N2 - In this contribution the current state in the field of Laser-Induced Periodic Surface Structures (LIPSS) is reviewed. This includes the mechanisms of formation and current applications, particularly the colorization of technical surfaces, the control of surface wetting properties, the tailoring of surface colonization by bacterial biofilms, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - PHOTONICA 2019 - The Seventh International School and Conference on Photonics CY - Belgrade, Serbia DA - 26.08.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Surface functionalization PY - 2019 UR - http://www.photonica.ac.rs/docs/PHOTONICA2019-Book_of_abstracts.pdf AN - OPUS4-48836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rades, Steffi A1 - Natte, Kishore A1 - Unger, Wolfgang T1 - NanoValid D.5.47 Annex 2 Inter-laboratory comparison on measurand surface charge (Zeta Potential) of silica particles: Report of the results N2 - An inter-laboratory comparison on the surface charge, expressed as zeta potential ζ, of nanoscaled SiO2 has been performed using #14 BAM Silica (see D.5.41/5.42) nanoparticles. The comparability of results delivered by participants has been tested. The Task 5.4 of NanoValid is designed to test, compare and validate current methods to measure and characterize physicochemical properties of selected engineered nanoparticles. The measurand is Surface charge expressed as zeta-Potential. The measurements are to be accompanied by estimates of the uncertainties at a confidence level of 95%, deduced from the standard uncertainties. Therefore an uncertainty budget comprising statistical (Type A) and systematic (Type B) errors has to be established and delivered for the measurand. The protocol comprises two Annexes addressing the establishment of uncertainty budgets following GUM. The final goal of the comparison is to identify those methods of measurement which have potential as reference methods in pc characterization of nanoparticles for the determination of a given measurand. KW - Inter-laborator comparison KW - Surface charge KW - Zeta potential KW - Uncertainty budget KW - Silica nanoparticles KW - NanoValid PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488483 DO - https://doi.org/10.5281/zenodo.3379815 SP - 1 EP - 10 PB - Zenodo CY - Geneva AN - OPUS4-48848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rades, Steffi A1 - Unger, Wolfgang T1 - NanoValid D.5.47 Annex 3 Inter-laboratory comparison on measurand specific surface area (BET) of nanoparticular Titania (#15 BAM Titania): Report of the results N2 - This Report describes an inter-laboratory comparison aiming on the establishment of the used method (BET) as a reference method. Another purpose was the certification of the porous reference material #15 BAM Titania as CRM BAM-P110 (cf. D 5.41/42). The certified values determined by nitrogen ad-sorption at 77.3 K according to the international standards ISO 15901-2 and ISO 9277 are summarized in the Table below. KW - Inter-laboratory comparison KW - Specific Surface Area (BET) KW - Nanoparticular TiO2 (Anatase) KW - EU FP7 project NanoValid PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488491 DO - https://doi.org/10.5281/zenodo.3379612 SP - 1 EP - 22 PB - Zenodo CY - Geneva AN - OPUS4-48849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Persson, K. A1 - Johansson Salazar-Sandoval, E. A1 - Ernstsson, M. A1 - Sundin, M. A1 - Wachtendorf, Volker A1 - Kunz, Valentin A1 - Unger, Wolfgang T1 - The EC4SafeNano Project - and the case study of Surface Chemical Transformations of Nano-TiO2 Samples upon Weathering N2 - A central challenge to ensure the sustainable production and use of nanotechnologies is to understand and effectively control the risks along the industrial innovation value chain. Knowledge about nanotechnology processes and nanosafety issues (hazards, fate, risk...) is growing rapidly but the effective use of this knowledge for risk management by market actors is lagging behind. EC4SafeNano (European Centre for Risk Management and Safe Innovation in Nanomaterials and Nanotechnologies) promotes a harmonized vision of expertise in risk assessment and management for the public and private sectors to enable the safe development and commercialization of nanotechnology. EC4SafeNano is operated together by major European risk institutes with the support of numerous associated partners, gathering all stakeholders involved in Nanomaterials and Nanotechnologies (regulators, industry, society, research, service providers...). In a case study the surface chemical transformations upon 2 different ageing procedures (long-term UV irradiation or swimming pool water) of a representative set of titanium dioxide nanoparticles has been investigated. The materials have been analyzed by various analytical techniques. Each method addresses different aspects of the complex endpoint surface chemistry. The multi technique approach allows evaluation of the capabilities and limitations of the applied methods regarding their suitability to address the endpoint surface chemistry and their sensitivity to identify even small surface chemical transformations. Results: - To obtain a comprehensive picture, it is insufficient to concentrate on a single analysis technique. - By using time-of-flight secondary ion mass spectrometry (ToF-SIMS) in combination with principal component analysis (PCA) it was possible to identify even subtle changes in the surface chemistry of the investigated materials. - A general trend that was observed for the UV-aged samples is the decrease of organic material on the nanomaterial surface. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 723623. T2 - FormulaX/NanoFormulation 2019 CY - Manchester, England, United Kingdom DA - 24.06.2019 KW - TiO2 nanoparticle KW - Surface Chemical Transformation KW - UV Weathering KW - SIMS KW - XPS KW - IR spectroscopy KW - EC4SafeNano PY - 2019 UR - https://www.formulation.org.uk/images/stories/FormulaX/Posters/P-14.pdf AN - OPUS4-48912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Breßler, Ingo T1 - SASfit and McSAS - Analyzing Small-Angle Scattering of Polymers N2 - Small-angle scattering (SAS) offers a reliable route to characterize the nanostructure of large amounts of material with a minimum of tedium, for example, easily extracting size distributions and volume fractions. There are a variety of analysis programs available while the evaluation of SAS measurements has been dominated by the classical curve fitting approach. SASfit represents such a classical curve fitting toolbox: it is one of the mature programs for SAS data analysis and has been available and used for many years. The latest developments will be presented and a scattering function of a mass fractal model of branched polymers in solution is provided as an example for implementing a plug-in. Alternatively to classical curve fitting, part two presents the latest developments of the user-friendly open-source Monte Carlo regression package McSAS. The form-free Monte Carlo nature of McSAS means, it is not necessary to provide further restrictions on the mathematical form of the parameter distribution: without prior knowledge, McSAS is able to extract complex multimodal or odd- shaped parameter distributions from SAS data. The headless mode is presented by an example of operation within interactive programming environments such as a Jupyter notebook. T2 - PolyDays 2019 CY - Berlin, Germany DA - 11.09.2019 KW - Small-angle scattering KW - SAXS KW - Software PY - 2019 AN - OPUS4-48958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, J. A1 - Tarábek, J. A1 - Kulkarni, R. A1 - Wang, Cui A1 - Dračínský, M. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Resch-Genger, Ute A1 - Bojdys, M. J. T1 - A π-conjugated, covalent phosphinine framework N2 - Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si and S have found their way into their building blocks so far. Here, we expand the toolbox available to polymer and materials chemists by one additional nonmetal, phosphorus. Starting with a building block that contains a λ⁵‐phosphinine (C₅P) moiety, we evaluate a number of polymerisation protocols, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) via Suzuki‐Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m2 g‐1 N2 BET at 77 K) with green fluorescence (λmax 546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h‐¹ g‐¹. Our results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties that might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis. KW - Phosphinine KW - Fully aromatic frameworks KW - Suzuki-Miyaura coupling KW - Polymers KW - Fluorescence KW - Small-angle scattering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485330 DO - https://doi.org/10.1002/chem.201900281 SP - 2 EP - 10 PB - Wiley VCH-Verlag CY - Weinheim AN - OPUS4-48533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Daneshnia, S. A1 - Adeli, M. A1 - Yari, A. A1 - Shams, A. A1 - Donskyi, Ievgen A1 - Unger, Wolfgang T1 - Low temperature functionalization of two-dimensional boron nitride for electrochemical sensing N2 - Two-dimensional hexagonal boron nitride(h-BN)as an emerging nanomaterial exhibits uniquephysicochemical properties, making it suitable candidate for a wide spectrum of applications.However, due to its poor functionality, the processability of this nanomaterial is low. In this work, wereport on a straightforward and scalable approach for the functionalization of h-BN by nitrene[2+1]cycloaddition at room temperature. The triazine-functionalized h-BN(Trz-BNs)showed ahigh reactivity toward nucleophiles, through which post-modifications are performable. The post-modification of Trz-BNs by L-cysteine was studied using cyclic voltammetry and differential pulsevoltammetry. Taking advantage of the scalable and straightforward functionalization as well as abilityof triazine functional groups for the controlled post-modifications, Trz-BNs is a promisingnanoplatform for a wide range of future applications. KW - Two-dimensional hexagonal boron nitride(h-BN) KW - Nitrene[2+1]cycloaddition KW - Post-modification by L-cysteine KW - Electrochemical sensing KW - XPS PY - 2019 DO - https://doi.org/10.1088/2053-1591/ab317b SN - 2053-1591 VL - 6 IS - 9 SP - 095076, 1 EP - 11 PB - IOP Publishing Ltd AN - OPUS4-48635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Gawek, Marcel A1 - Madkour, S. A1 - Schönhals, Andreas T1 - Confinement and localization effects revealed for thin films of the miscible blend Poly(vinyl methyl ether) / Polystyrene with a composition of 25/75 wt% N2 - Thin films (200-7nm) of the asymmetric polymer blend poly(vinyl methyl ether) (PVME)/polystyrene (PS) (25/75wt%) were investigated by broadband dielectric spectroscopy (BDS). Thicker samples ([Formula: see text]37 nm) were measured by crossed electrode capacitors (CEC), where the film is capped between Al-electrodes. For thinner films ([Formula: see text]37 nm) nanostructured capacitors (NSC) were employed, allowing one free surface in the film. The dielectric spectra of the thick films showed three relaxation processes ( [Formula: see text] -, [Formula: see text] - and [Formula: see text] -relaxation), like the bulk, related to PVME fluctuations in local spatial regions with different PS concentrations. The thickness dependence of the [Formula: see text] -process for films measured by CECs proved a spatially heterogeneous structure across the film with a PS-adsorption at the Al-electrodes. On the contrary, for the films measured by NSCs a PVME segregation at the free surface was found, resulting in faster dynamics, compared to the CECs. Moreover, for the thinnest films ([Formula: see text]26 nm) an additional relaxation process was detected. It was assigned to restricted fluctuations of PVME segments within the loosely bounded part of the adsorbed layer, proving that for NSCs a PVME enrichment takes place also at the polymer/substrate interface. KW - Thin polymer films KW - Broadband dielectric spectroscopy PY - 2019 DO - https://doi.org/10.1140/epje/i2019-11870-3 SN - 1292-895X VL - 42 IS - 8 SP - 101, 1 EP - 11 PB - Springer AN - OPUS4-48651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fletcher, D. C. A1 - Hunter, R. A1 - Xia, W. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Blackburn, E. A1 - Kulak, A. A1 - Xin, H. A1 - Schnepp, Z. T1 - Scalable synthesis of dispersible iron carbide (Fe3C) nanoparticles by ‘nanocasting’ N2 - Metal carbides have shown great promise in a wide range of applications due to their unique catalytic, electrocatalytic and magnetic properties. However, the scalable production of dispersible metal carbide nanoparticles remains a challenge. Here, we report a simple and scalable route to dispersible iron carbide (Fe3C) nanoparticles. This uses MgO nanoparticles as a removable ‘cast’ to synthesize Fe3C nanoparticles from Prussian blue (KFeIII[FeII(CN)6]). Electron tomography demonstrates how nanoparticles of the MgO cast encase the Fe3C nanoparticles to prevent sintering and agglomeration during the high-temperature synthesis. The MgO cast is readily removed with ethylenediaminetetraacetic acid (EDTA) to generate Fe3C nanoparticles that can be used to produce a colloidal ferrofluid or dispersed on a support material. KW - Small-angle scattering KW - SAXS KW - Metal carbides KW - Nanoparticles KW - Nanocasting PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486295 DO - https://doi.org/10.1039/C9TA06876G SN - 2050-7488 SN - 2050-7496 VL - 7 IS - 33 SP - 19506 EP - 19512 PB - Royal Society of Chemistry (RSC) AN - OPUS4-48629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Advanced characterization of nanomaterials N2 - The rational synthesis and use of nanomaterials require the characterization of many different properties, ranging from particle size and size distribution over surface chemistry to more applicationrelevant features like optical, electrochemical, and magnetic properties. In the following, several methods for the characterization of functional groups on nanomaterials, like polymer and silica nanoparticles, semiconductor quantum dots, and lanthanide-based upconversion nanocrystals are presented. Additionally, procedures for the measurement of the key spectroscopic performance parameters of nanomaterials with linear and nonlinear photoluminescence, such as the photoluminescence quantum yield, are presented for the UV/vis/NIR/SWIR. T2 - Summerschool CY - Bad Honnef, Germany DA - 22.07.2019 KW - Quantum yield KW - Nanoparticle KW - Fluorescence KW - Quantum dot KW - NIR KW - SWIR KW - Quality assurance KW - Calibration PY - 2019 AN - OPUS4-48630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiesholler, L. M. A1 - Frenzel, Florian A1 - Grauel, Bettina A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Hirsch, T. ED - Resch-Genger, Ute ED - Hirsch, Thomas T1 - Yb,Nd,Er-doped upconversion nanoparticles: 980 nm versus 808 nm excitation N2 - Yb,Nd,Er-doped upconversion nanoparticles (UCNPs) have attracted considerable interest as luminescent reporters for bioimaging, sensing, energy conversion/shaping, and anticounterfeiting due to their capability to convert multiple near-infrared (NIR) photons into shorter wavelength ultraviolet, visible or NIR luminescence by successive absorption of two or more NIR photons. This enables optical measurements in complex media with very little background and high penetration depths for bioimaging. The use of Nd3+ as substitute for the commonly employed sensitizer Yb3+ or in combination with Yb3+ shifts the excitation wavelength from about 980 nm, where the absorption of water can weaken upconversion luminescence, to about 800 nm, and laser-induced local overheating effects in cells, tissue, and live animal studies can be minimized. To systematically investigate the potential of Nd3+ doping, we assessed the performance of a set of similarly sized Yb3+,Nd3+,Er3+-doped core- and core–shell UCNPs of different particle architecture in water at broadly varied excitation power densities (P) with steady state and time-resolved fluorometry for excitation at 980 nm and 808 nm. As a measure for UCNPs performance, the P-dependent upconversion quantum yield (Φ) and its saturation behavior were used as well as particle brightness (B). Based upon spectroscopic measurements at both excitation wavelengths in water and in a lipid phantom and B-based calculations of signal size at different penetration depths, conditions under which excitation at 808 nm is advantageous are derived and parameters for the further optimization of triple-doped UCNPs are given. KW - Lanthanide KW - Upconversion KW - Nanoparticle KW - Photoluminescence KW - Quantum yield KW - Lifetime KW - Brightness KW - Nd excitation KW - Excitation power density KW - Modelling KW - NIR PY - 2019 DO - https://doi.org/10.1039/C9NR03127H SN - 2040-3372 SN - 2040-3364 VL - 11 IS - 28 SP - 13440 EP - 13449 PB - Royal Society of Chemistry CY - London AN - OPUS4-48608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Brunet, G. A1 - Marin, R. A1 - Monk, Melissa-Jane A1 - Galico, D. A. A1 - Sigoli, F. A. A1 - Suturina, E. A. A1 - Hemmer, E. A1 - Murugesu, M. T1 - Exploring the dual functionality of an Ytterbium complex for luminescence thermometry and slow magnetic relaxation† N2 - We present a comprehensive investigation of the magnetic and optical properties of an ytterbium complex, which combines two desirable and practical features into a single molecular system. Based upon YbIII Ions that promote near-infrared optical activity and a chemical backbone that is ideal for an in-depth understanding of the magnetic behaviour, we have designed a multifunctional opto-magnetic species that operates as a luminescent thermometer and as a single-molecule magnet (SMM). Our magnetic investigations, in conjunction with ab initio calculations, reveal one of the highest energy barriers reported for an YbIII-based complex. Moreover, we correlate this anisotropic barrier with the Emission spectrum of the compound, wherein we provide a complete assignment of the energetic profile of the complex. Such studies lay the foundation for the design of exciting multi-faceted materials that are able to retain information at the single-molecule level and possess built-in thermal self-monitoring capabilities. KW - Magnetic KW - Fluorescence KW - NIR KW - Temperature KW - Dual sensing KW - Sensor KW - Yb(III) complex KW - Lanthanide KW - Quantum yield KW - Quality assurance PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486659 DO - https://doi.org/10.1039/c9sc00343f VL - 10 IS - 28 SP - 6799 EP - 6808 PB - Royal Society of Chemistry AN - OPUS4-48665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - High-Quality Experimental Data in Electron Microscopy and Microanalysis – What can, and should we jointly do? N2 - There are different ways how to prove the quality of the results obtained by electron microscopy and related microanalysis techniques, e.g. use of validated standard operation procedures, participation in proficiency testing exercises, use of certified reference materials, etc. International standards are able to provide requirements, specifications, guidelines or characteristics of methods, instruments or samples with the final goal that these can be used consistently in accredited laboratories. In the field of electron microscopy and microbeam analysis standardization and metrology are terms which are encountered rather seldom at major conferences and scientific publications. Nevertheless, spectra formats like EMSA/MSA for spectral-data exchange or tagged image file format (TIFF) for SEM, guidelines for performing quality assurance procedures or for the specification of X-ray spectrometers as well as of certified reference materials (CRMs) in EPMA, or measurement of average grain size by electron backscatter diffraction (EBSD), or guidelines for calibrating image magnification in SEM or TEM are ISO standards already published and used successfully by a large part of the electron microscopy and microbeam analysis community. A main and continuous task of ISO/TC 202 and its subcommittees is to identify and evaluate feasible projects/proposals needed to be developed into new international standards, particularly in respect to recent but established technology, such the silicon drift detector (SDD) EDS one. Another international platform in the frame of which pre-standardization work can be organized is VAMAS (Versailles Project on Advanced Materials and Standards). International collaborative projects involving aim at providing the technical basis for harmonized measurements, testing, specifications, and standards to be further developed at ISO level. One key point of VAMAS activities is constituted by inter-laboratory comparisons for high-quality data. In the field of microbeam analysis, the technical working area (TWA) 37 Quantitative Microstructural Analysis deals with corresponding projects. Good ideas, e.g. on analysis of low-Z materials/elements and at low energies are particularly encouraged by directly contacting the author. Support and already available guidance will be supplied. T2 - Microscopy & Microanalysis 2019 CY - Portland, OR, USA DA - 03.08.2019 KW - Pre-standardisation KW - Inter-laboratory comparison KW - VAMAS KW - ISO KW - Electron microscopy KW - Microanalysis PY - 2019 AN - OPUS4-48672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guday, G. A1 - Donskyi, Ievgen A1 - Gholami, M. F. A1 - Algara-Siller, G. A1 - Witte, F. A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Paulus, B. A1 - Rabe, J. A1 - Adeli, M. A1 - Haag, R. T1 - Scalable Production of Nanographene and Doping via Nondestructive Covalent Functionalization N2 - A new method for top‐down, one‐pot, gram‐scale production of high quality nanographene by incubating graphite in a dilute sodium hypochlorite solution at only 40 °C is reported here. The produced sheets have only 4 at% oxygen content, comparable with nanographene grown by chemical vapor deposition. The nanographene sheets are covalently functionalized using a nondestructive nitrene [2+1] cycloaddition reaction that preserves their π‐conjugated system. Statistical analyses of Raman spectroscopy and X‐ray photoelectron spectroscopy indicate a low number of sp3 carbon atoms on the order of 2% before and 4% after covalent functionalization. The nanographene sheets are significantly more conductive than conventionally prepared nanographene oxide, and conductivity further increases after covalent functionalization. The observed doping effects and theoretical studies suggest sp2 hybridization for the carbon atoms involved in the [2+1] cycloaddition reaction leading to preservation of the π‐conjugated system and enhancing conductivity via n‐type doping through the bridging N‐atom. These methods are easily scalable, which opens the door to a mild and efficient process to produce high quality nanographenes and covalently functionalize them while retaining or improving their physicochemical properties. KW - Graphene KW - XPS KW - NEXAFS PY - 2019 DO - https://doi.org/10.1002/smll.201805430 VL - 15 IS - 12 SP - 1805430 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Potthoff, A. A1 - Unger, Wolfgang T1 - Report on SOP for dispersing nanomaterials in water and report on round robin test. N2 - This report describes a standard operation procedure for dispersion of nanomaterials in liquids prior to toxicological or ecotoxicological testing. Main factors, who determine the state of agglomeration and aggregation of ENMs after dispersion are specific energy input, particle concentration and fluid composition. The method was validated in two round robin tests, where two typical nanomaterials (a nanopowder and a nanodispersion) were investigated. One main result arising out of the data comparison was that only those participants, who were able to follow the instructions in the SOPs completely, received similar results regarding particle size and zeta potential. The SOP is easy to adapt for other types of nanomaterials. The results provide the standardization process and were presented at DIN working group. KW - Dispersion of nano materials KW - AEROSIL® OX50 KW - LEVASIL 50/50 PY - 2019 UR - http://publica.fraunhofer.de/documents/N-541033.html DO - https://doi.org/10.24406/ikts-n-541033 SP - 1 EP - 24 AN - OPUS4-48022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Essmann, M. A1 - Becker, S. F. A1 - Witt, Julia A1 - Zhan, J. A1 - Chimeh, A. A1 - Korte, A. A1 - Zhong, J. A1 - Vogelgesang, R. A1 - Wittstock, G. A1 - Lienau, C. T1 - Vectorial near-field coupling N2 - The coherent exchange of optical near fields between two neighbouring dipoles plays an essential role in the optical properties, quantum dynamics and thus the function of many naturally occurring and artificial nanosystems. These interactions are challenging to quantify experimentally. They extend over only a few nanometres and depend sensitively on the detuning, dephasing and relative orientation (that is, the vectorial properties) of the coupled dipoles. Here, we introduce plasmonic nanofocusing spectroscopy to record coherent light scattering spectra with 5 nm spatial resolution from the apex of a conical gold nanotaper. The apex is excited solely by evanescent fields and coupled to plasmon resonances in a single gold nanorod. We resolve resonance energy shifts and line broadenings as a function of dipole distance and relative orientation. We demonstrate how These phenomena arise from mode couplings between different vectorial components of the interacting optical near fields, specifically from the coupling of the nanorod to both transverse and longitudinal polarizabilities of the taper apex. KW - Plasmon resonance KW - Coherent exchange KW - Optical near field KW - Plasmonic nanofocusing spectroscopy PY - 2019 DO - https://doi.org/10.1038/s41565-019-0441-y SN - 1748-3387 VL - 14 IS - 7 SP - 698 EP - 704 PB - Nature AN - OPUS4-48028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martynenko, Irina V. ED - Baimuratov, A. S. ED - Weigert, Florian ED - Soares, J. X. ED - Dhamo, Lorena ED - Nickl, Philip ED - Doerfel, I. ED - Pauli, Jutta ED - Rukhlenko, I. D. ED - Baranov, A. V. ED - Resch-Genger, Ute T1 - Photoluminescence of Ag–In–S/ZnS quantum dots: Excitation energy dependence and low-energy electronic structure N2 - Cd-free I–III–VI group semiconductor quantum dots (QDs) like Ag–In–S and Cu–In–S show unstructured absorption spectra with a pronounced Urbach tail, rendering the determination of their band gap energy (Eg) and the energy structure of the exciton difficult. Additionally, the origin of the broad photoluminescence (PL) band with lifetimes of several hundred nanoseconds is still debated. This encouraged us to study the excitation energy dependence (EED) of the PL maxima, PL spectral band widths, quantum yields (QYs), and decay kinetics of AIS/ZnS QDs of different size, composition, and surface capping ligands. These results were then correlated with the second derivatives of the corresponding absorption spectra. The excellent match between the onset of changes in PL band position and spectral width with the minima found for the second derivatives of the absorption spectra underlines the potential of the EED approach for deriving Eg values of these ternary QDs from PL data. The PL QY is, however, independent of excitation energy in the energy range studied. From the EED of the PL features of the AIS/ZnS QDs we could also derive a mechanism of the formation of the low-energy electronic structure. This was additionally confirmed by a comparison of the EED of PL data of as-synthesized and size-selected QD ensembles and the comparison of these PL data with PL spectra of single QDs. These results indicate a strong contribution of intrinsic inhomogeneous PL broadening to the overall emission features of AIS/ZnS QDs originating from radiative transitions from a set of energy states of defects localized at different positions within the quantum dot volume, in addition to contributions from dimensional and chemical broadening. This mechanism was confirmed by numerically modelling the absorption and PL energies with a simple mass approximation for spherical QDs and a modified donor–acceptor model, thereby utilizing the advantages of previously proposed PL mechanisms of ternary QDs. These findings will pave the road to a deeper understanding of the nature of PL in quantum confined I–III–VI group semiconductor nanomaterials. KW - Core/shell quantum dot KW - Silver indium sulfide KW - Defect photoluminescence KW - Photoluminescence quantum yield KW - Single-dot spectroscopy PY - 2019 DO - https://doi.org/10.1007/s12274-019-2398-4 SN - 1998-0124 SN - 1998-0000 VL - 12 IS - 7 SP - 1595 EP - 1603 PB - Springer Nature AN - OPUS4-48503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Kotil, L. A1 - Hodoroaba, Vasile-Dan A1 - Bernsmeier, Denis A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Spectroscopic ellipsometric analysis of elemental composition and porosity of mesoporous iridium-titanium mixed oxide thin films for electrocatalytic splitting of water N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge for modern analytical techniques and requires approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by spectroscopic ellipsometry (SE). Mesoporous iridium oxide - titanium oxide (IrOx-TiOx) films were prepared via dip-coating of a solution containing a triblock-copolymer as structure-directing agent, an iridium precursor as well as a titanium precursor in ethanol. Deposited films with different amounts of iridium (0 wt%Ir to 100 wt%Ir) were synthesized and calcined in air. The thin films were analyzed with SE using the Bruggeman effective medium approximation (BEMA) for modelling. The results were compared with electron probe microanalysis (EPMA) as part of a combined SEM/EDS/STRATAGem Analysis. T2 - 8th International conference on spectroscopic ellipsometry (ICSE-8) CY - Barcelona, Spain DA - 26.05.2019 KW - Mesoporous iridium-titanium mixed oxides KW - Thin films KW - Spectroscopic ellipsometry KW - Oxygen evolution reaction KW - EPMA KW - Ellipsometric porosimetry PY - 2019 AN - OPUS4-48387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rühle, Bastian A1 - Virmani, E. A1 - Engelke, H. A1 - Hinterholzinger, F. M. A1 - von Zons, T. A1 - Brosent, B. A1 - Bein, T. A1 - Godt, A. A1 - Wuttke, S. T1 - A Chemiluminescent Metal–Organic Framework N2 - The synthesis and characterization of a chemiluminescent metal–organic framework with high porosity is reported. It consists of Zr6O6(OH)4 nodes connected by 4,4′‐(anthracene‐9,10‐diyl)dibenzoate as the linker and luminophore. It shows the topology known for UiO‐66 and is therefore denoted PAP‐UiO. The MOF was not only obtained as bulk material but also as a thin film. Exposure of PAP‐UiO as bulk or film to a mixture of bis‐(2,4,6‐trichlorophenyl) oxalate, hydrogen peroxide, and sodium salicylate in a mixture of dimethyl and dibutyl phthalate evoked strong and long lasting chemiluminescence of the PAP‐UiO crystals. Time dependent fluorescence spectroscopy on bulk PAP‐UiO and, for comparison, on dimethyl 4,4′‐(anthracene‐9,10‐diyl)dibenzoate provided evidence that the chemiluminescence originates from luminophores being part of the PAP‐UiO, including the luminophores inside the crystals. KW - Chemiluminescence KW - Metal–organic framework KW - MOF KW - Thin film KW - UiO PY - 2019 DO - https://doi.org/10.1002/chem.201806041 SN - 0947-6539 VL - 25 IS - 25 SP - 6349 EP - 6354 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Pauli, Jutta A1 - Würth, Christian A1 - Güttler, Arne A1 - Richter, Maria A1 - Schneider, Thomas T1 - Determining Photoluminescence Quantum Yields of Molecular and Nanocrystal Emitters in the UV/vis/NIR/SWIR N2 - The comparison of different emitter classes and the rational design of the next generation of molecular and nanoscale reporters require accurate and quantitative photo-luminescence measurements. This is of special importance for all photoluminescence applications in the life and material sciences and nanobiophotonics. In the following, procedures for the determination of the spectroscopic key parameter photoluminescence quantum yield, i.e., the number of emitted per absorbed photons, in the UV/vis/NIR/SWIR are presented including pitfalls and achievable uncertainties and material-specific effects related to certain emitter classes are addressed. T2 - Kolloqium National Center for Nanoscience and Technology CY - Peking, People's Republic of China DA - 18.10.2019 KW - Fluorescence KW - Quantum yield KW - Integrating sphere spectroscopy KW - Dye KW - Nanocrystal KW - NIR KW - SWIR KW - Quantum dot KW - Fluorescence standard KW - Uncertainty KW - Calibration PY - 2019 AN - OPUS4-49362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harris, J. A1 - Mey, I. P. A1 - Böhm, C. F. A1 - Trinh, T. T. H. A1 - Fink, A. A1 - Bayer, F. A1 - Leupold, S. A1 - Prinz, Carsten A1 - Tripal, P. A1 - Palmisano, R. A1 - Wolf, S. E. T1 - Ultra-smooth and space-filling mineral films generated via particle accretion processes N2 - Nonclassical crystallization typically occurs via the attachment of individual nanoparticles. Intuitively, materials synthesized via this route should exhibit pronounced surface roughness and porosity as a hallmark of the formation process via particle accretion. Here, we demonstrate that nonclassical mineralization of calcium carbonate allows synthesis of ultra-smooth and dense surfaces with unprece-dented root-mean-square roughness of 0.285 nm, simply by con-trolling the hydration state of the nanosized building blocks using Mg doping. High fidelity coating of corrugated substrates can even be achieved. Nonclassical crystallization can thus lead to space-filling inorganic solid-state materials transgressing the implicit porosity commonly expected for particle-driven self-organization processes. KW - Nonclassical crystallization KW - Hydration KW - Particle accretion PY - 2019 DO - https://doi.org/10.1039/c9nh00175a VL - 4 IS - 6 SP - 1388 EP - 1393 PB - Royal Society of Chemistry AN - OPUS4-49488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Yamamoto, K. A1 - Grulke, E. A. A1 - Maurino, V. ED - Bosse, H. ED - Buhr, E. ED - Dziomba, T. ED - Hodoroaba, Vasile-Dan ED - Klein, T. ED - Krumrey, M. T1 - Shape controlled TiO2 nanoparticles as candidates for nano-CRM’s – an ISO case study N2 - Extraction of true, 3D shape (and size) of non-spherical nanoparticles (NPs) is associated with Errors by conventional 2D electron microscopy using projection images. Significant efforts within the ISO technical committee TC 229 ‘Nanotechnologies’ are aimed at establishing accurate TEM and SEM measurement of NP size and shape as robust, standard procedures. Study groups have been organizing inter-laboratory comparisons on well-selected NP systems according to the market needs, such as aggregated titania nano-powder for which size and shape distribution of primary crystallites of irregular shape must be measured accurately. To be noticed is e. g. the fact that the measurement procedure allows only manual selection of the particles clearly distinguishable for analysis as well as manual definition of the contour of the imaged NPs. An inter-laboratory exercise on titania NPs (pure anatase, grown by hydrothermal synthesis) of well-defined non-spherical shape, i.e. bipyramidal, has been recently started within ISO/TC 229 under similar conditions as for the irregular shaped titania. In the TEM micrograph the particles tracked manually according to the measurement protocol. Overlapped particles were allowed to be considered, as long as they are clearly distinguishable. One decisive NP selection criterion was to analyze only those NPs with a roundness value below 0.7, i.e. the NPs laying on the support foil and, hence, with projection areas clearly deviating from perfect circles (R=1). The overall evaluation (for 15 labs) of the size descriptors (area, Feret, minFeret, perimeter) and shape descriptors (aspect ratio, roundness, compactness, extent) by analysis of variance is just to be finished and included in ISO/WD 21363 Nanotechnologies -- Protocol for particle size distribution by transmission electron microscopy. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Titanium dioxide KW - Nanoparticles KW - Shape-controlled KW - Electron microscopy PY - 2019 SN - 978-3-95606-440-1 DO - https://doi.org/https://doi.org/10.7795/110.20190412 SN - 0179-0609 VL - F-61 SP - 245 EP - 255 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mech, A. A1 - Gaillard, C. A1 - Marvin, H. A1 - Wohlleben, W. A1 - Hodoroaba, Vasile-Dan A1 - Babick, F. A1 - Friedrich, C. M. A1 - Brüngel, R. A1 - Rückert, J. A1 - Ghanem, A. A1 - Weigel, S. T1 - The NanoDefine Decision Framework and NanoDefiner e-Tool: a practical guide to the identification of nanomaterials N2 - The European Commission's recommendation on the definition of nanomaterial [2011/696/EU] is broadly applicable across different regulatory sectors and requires the quantitative size Determination of constituent particles in samples down to 1 nm. A material is a nanomaterial if 50 % or more of the particles are in the size range 1-100 nm. The implementation of the definition in a regulatory context challenges measurement methods to reliably identify nanomaterials and ideally also nonnanomaterials as substance or product ingredient as well as in various matrices. The EU FP7 NanoDefine project [www.nanodefine.eu] addressed these challenges by developing a robust, readily implementable and cost-effective measurement strategy to decide for the widest possible range of materials whether it is a nanomaterial or not. It is based on existing and emerging particle measurement techniques evaluated against harmonized, material-dependent performance criteria and by intra- and inter-lab comparisons. Procedures were established to reliably measure the size of particles within 1-100 nm, and beyond, taking into account different shapes, coatings and chemical compositions in industrial materials and consumer products. Case studies prove their applicability for various sectors, including food, pigments and cosmetics. A main outcome is the establishment of an integrated tiered approach including rapid screening (Tier 1) and confirmatory methods (tier 2), a decision support flow scheme and a user manual to guide end-users, such as manufacturers, in selecting appropriate methods. Another main product is the “NanoDefiner” e-Tool which implements the flow scheme in a user-friendly software and guides the user in a semi-automated way through the entire decision procedure. It allows a cost-effective selection of appropriate methods for material classification according to the EC's nanomaterial definition and provides a comprehensive report with extensive explanation of all decision steps to arrive at a transparent identification of nanomaterials as well as non-nanomaterials for regulatory purposes. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Definition of nanomaterial KW - Regulation PY - 2019 SN - 978-3-95606-440-1 SN - 0179-0609 VL - F-61 SP - 114 EP - 124 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maurino, V. A1 - Pellutiè, L. A1 - Pellegrino, F. A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Isopescu, R. T1 - Synthesis of size and shape controlled TiO2 nanoparticles: possible CRM’s candidates for size, shape and functional properties N2 - Titanium dioxide is one of the most studied metal oxides due to its chemical, surface, electronic and (photo)catalytic properties, providing this material of multisectorial applications ranging from healthcare, photocatalysis, smart materials with self cleaning and self sterilizing properties and solar energy harvesting. However it is difficult to correlate the functional properties of TiO2 nanomaterials to the properties at single nanoparticle level due to the high polydispersity in shape, size and surface features of the currently available TiO2 nanoparticles (NPs). Although intensive experimental and theoretical studies have been conducted on the reactivity of different surfaces of metal oxides such as TiO2 much less attention is paid on the dependence of functional properties, like photocatalytic activity, dye adsorption, open circuit potential and fill factor in dye sensitized solar cells, on crystal facets in different orientations. One of the goal of SETNanoMetro project was the development of design rules to tune crystal facets of TiO2 NPs in order to optimize and control functional properties. In the present work we have developed a series of design rules in order to obtain sets of anatase TiO2 NPs with low polydispersity and to tune their shape and size by hydrothermal processing of Ti(IV)- Triethanolamine complex in presence of different shape controllers. Through a careful experimental design, a predictive soft model was developed. The model is able to predict the synthesis outcome allowing to tune the shape factor from 5 (prisms) to 1.5 (bipyramids) to 0.2 (platelets). This allows to control the main crystal facets exposed ranging from (100) to (001). Due to the dependence of functional properties of nanomaterials on shape distribution and not only size, the availability of NPs sets with uniform and well defined and tunable shapes can be of paramount relevance in order to produce reference nanomaterials for shape measurement. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Anatase KW - shape control KW - Hydrothermal synthesis PY - 2019 SN - 978-3-95606-440-1 SN - 0179-0609 VL - F-61 SP - 146 EP - 162 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Backes, Sebastian A1 - Fahrbach, M. A1 - Cappella, Brunero A1 - Peiner, E. T1 - Scanning characterization of polymer coating layers using contact resonance with piezoresistive microprobes N2 - The motivation and the measurement setup for large fast-scanning piezoresistive cantilevers are presented. The theory behind the measurements of mechanical properties through contact resonance is explained. Results of such measurements on two kinds of polymer are compared to results from force distance curves. Noise, time-dependency and dependency of the results on the vibration mode are identified as challenges of contact resonance. T2 - 19th International Conference and Exhibition (European Society for Precision engineering and Nanotechnology/EUSPEN) CY - Bilbao, Spain DA - 03.06.2019 KW - Force distance curves KW - Contact resonance KW - Lubricants KW - Photoresist PY - 2019 AN - OPUS4-49903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Backes, Sebastian A1 - Cappella, Brunero T1 - Force distance curves (FDC) & contact resionance (CR) measurement modes for mechanical property measurements N2 - At the Stakeholder meeting of the EMPIR project “Multifunctional ultrafast microprobes for on-the-machine measurements”, details about two measurement modes were presented. Force distance curves and contact resonance measurements are compared. The basic principles are explained and exemplary measurements concerning mechanical properties of polymers are shown. T2 - 19th International Conference and Exhibition (European Society for Precision Engineering and Nanotechnology/EUSPEN) CY - Bilbao, Spain DA - 03.06.2019 KW - Force distance curve KW - Contact resonance KW - Lubricants KW - Photoresist PY - 2019 AN - OPUS4-49905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Sebastian A1 - Cappella, Brunero T1 - Characterization of lubricants using AFM force-distance curves N2 - Auf dünnen Filmen von Schmiermitteln wurden Kraft-Abstand-Kurven aufgenommen. Die Schmiermittel benetzen die AFM-Spitze, sodass eine Kapillarkraft auftritt. Diese hängt von der Form der Spitze sowie von physikalischen Eigenschaften wie Viskosität und Oberflächenspannung ab, die zusätzlich mit anderen Verfahren bestimmt wurden. So konnte ihr Einfluss auf die Kurvenform untersucht werden. N2 - Force-distance curves have been recorded on thin films of lubricants. The lubricants wet the AFM tip, which causes a capillary force. This force depends on the shape of the tip, as well as on physical properties like viscosity and surface tension, which have been determined additionally with other methods. This way, their influence on the shape of the curves could be analyzed. T2 - 60. Tribologie-Fachtagung der Gesellschaft für Tribologie/GfT CY - Göttingen, Germany DA - 23.09.2019 KW - AFM-Kraft-Abstand-Kurven KW - Schmiermittel KW - Viskosität PY - 2019 AN - OPUS4-49906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nirmalananthan-Budau, Nithiya A1 - Rühle, Bastian A1 - Geißler, Daniel A1 - Moser, Marko A1 - Kläber, Christopher A1 - Schäfer, A. A1 - Resch-Genger, Ute T1 - Multimodal cleavable reporters for quantifying carboxy and amino groups on organic and inorganic nanoparticles N2 - Organic and inorganic nanoparticles (NPs) are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. These applications require knowledge of the chemical nature, total number of surface groups, and the number of groups accessible for subsequent coupling of e.g., antifouling ligands, targeting bioligands, or sensor molecules. To establish the concept of catch-and-release assays, cleavable probes were rationally designed from a quantitatively cleavable disulfide moiety and the optically detectable reporter 2-thiopyridone (2-TP). For quantifying surface groups on nanomaterials, first, a set of monodisperse carboxy-and amino-functionalized, 100 nm-sized polymer and silica NPs with different surface group densities was synthesized. Subsequently, the accessible functional groups (FGs) were quantified via optical spectroscopy of the cleaved off reporter after its release in solution. Method validation was done with inductively coupled plasma optical emission spectroscopy (ICP-OES) utilizing the sulfur atom of the cleavable probe. This comparison underlined the reliability and versatility of our probes, which can be used for surface group quantification on all types of transparent, scattering, absorbing and/or fluorescent particles. The correlation between the total and accessible number of FGs quantified by conductometric titration, qNMR, and with our cleavable probes, together with the comparison to results of conjugation studies with differently sized biomolecules reveal the potential of catch-and-release reporters for surface analysis. Our findings also underline the importance of quantifying particularly the accessible amount of FGs for many applications of NPs in the life sciences. KW - Advanced Materials KW - Surface Chemistry KW - Organic–inorganic nanostructures KW - Funtional Groups KW - Quantitative Analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499081 DO - https://doi.org/10.1038/s41598-019-53773-3 VL - 9 SP - 17577-1 EP - 17577-11 PB - Springer Nature CY - London AN - OPUS4-49908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sentker, K. A1 - Yildirim, Arda A1 - Lippmann, M. A1 - Zantop, A. W. A1 - Bertram, F. A1 - Hofmann, T. A1 - Seeck, O. H. A1 - Kityk, A. A1 - Mazza, M. G. A1 - Schönhals, Andreas A1 - Huber, P. T1 - Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials N2 - Nanoporous media exhibit structures significantly smaller than the wavelengths of visible light and can thus act as photonic metamaterials. Their optical functionality is not determined by the properties of the base materials, but rather by tailored, multiscale structures, in terms of precise pore shape, geometry, and orientation. Embedding liquid crystals in pore space provides additional opportunities to control light–matter interactions at the single-pore, meta-atomic scale. Here, we present temperature-dependent 3D reciprocal space mapping using synchrotron-based X-ray diffraction in combination with high-Resolution birefringence experiments on disk-like mesogens (HAT6) imbibed in self-ordered arrays of parallel cylindrical pores 17 to 160 nm across in monolithic anodic aluminium oxide (AAO). In agreement with Monte Carlo computer simulations we observe a remarkably rich self-assembly behaviour, unknown from the bulk state. It encompasses transitions between the isotropic liquid state and discotic stacking in linear columns as well as circular concentric ring formation perpendicular and parallel to the pore axis. These textural transitions underpin an optical birefringence functionality, tuneable in magnitude and in sign from positive to negative via pore size, pore surface-grafting and temperature. Our study demonstrates that the advent of large-scale, self-organised nanoporosity in monolithic solids along with confinement-controllable phase behaviour of liquid-crystalline matter at the single-pore scale provides a reliable and accessible tool to design materials with adjustable optical anisotropy, and thus offers versatile pathways to finetune polarisation-dependent light propagation speeds in materials. Such a tailorability is at the core of the emerging field of transformative optics, allowing, e.g., adjustable light absorbers and extremely thin metalenses. KW - Discotic Liquid Crystals PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499601 DO - https://doi.org/10.1039/c9nr07143a SP - 1 EP - 14 PB - RSC Royal Society of Chemistry AN - OPUS4-49960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meierhofer, F. A1 - Dissinger, F. A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Waldvogel, S. R. A1 - Voss, T. T1 - Citric-Acid-Based Carbon Dots with Luminescence Quantum Yields > 50%: spectral tuning of the luminescence by ligand exchange and pH adjustment N2 - We report the synthesis and characterization of carbon nanodots (CDs) with high quantum yield (>50%) and tailored optical absorption as well as emission properties. A well-described protocol with polyethyleneimine (PEI) as amine precursor is used as a reference to a new CD system which is stabilized by aromatic 2,3-diaminopyridine (DAP) molecules instead. The DAP stabilizer is installed in order to red-shift the absorption peak of the n-π* electron transition allowing efficient radiative recombination and light emission. Size, shape, and chemical composition of the samples are determined by (HR)TEM, EDX and FTIR-spectroscopy. Optical parameters are investigated using UV-VIS, PL and QY measurements. Several parameters such as concentration, excitation wavelength and pH are studied. Zeta-potential analysis indicate that pH-induced (de-)protonation processes of functional moieties directly affect the n-π* energy bands. This results in unique pH-dependent absorption and emission characteristics which are discussed on the specific chemical composition of each CD system. T2 - MRS 2019 CY - Boston, MA, USA DA - 03.12.2019 KW - Nanoparticle KW - Carbon dot KW - Surface chemistry KW - Fluorescence KW - PH KW - Ligand KW - FTIR KW - Synthesis KW - Characterization PY - 2019 AN - OPUS4-49968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frielinghaus, H. A1 - Butler, P. D. A1 - Pauw, Brian Richard A1 - Rennie, A. R. T1 - Eleventh canSAS Meeting: International Cooperation and Collaboration in Small-Angle Scattering N2 - The eleventh canSAS workshop was held in Freising, Germany, July 8–10, 2019. These international meetings, promoting collective action for nomadic small-angle scatterers, have been taking place since 1998 and act as forums to catalyze cooperation amongst the SAS community in order to provide better facilities and equipment, combined with reliable data interpretation and analysis. The meeting attracted over 60 participants from major neutron and X-ray laboratories, as well as manufacturers of SAXS equipment, and users from academia and industry. There was also a wide geographical spread with participants from Australia, Asia, and North America joining European colleagues. T2 - canSAS XI CY - Freising, Germany DA - 08.07-2019 KW - Small angle scattering KW - Conference KW - Standardisation PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498192 DO - https://doi.org/10.1080/08940886.2019.1680215 SN - 0894-0886 SN - 1931-7344 VL - 32 IS - 6 SP - 48 EP - 49 PB - Taylor & Francis CY - Abingdon, UK AN - OPUS4-49819 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kockert, M. A1 - Mitdank, R. A1 - Zykov, A. A1 - Kowarik, Stefan A1 - Fischer, F. T1 - Absolute Seebeck coefficient of thin platinum films N2 - The influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. Structural properties, like the film thickness and the grain size, are varied. We correlate the electron mean free path with the temperature dependence of the electrical conductivity and the absolute Seebeck coefficient SPt of platinum. A measurement platform was developed as a standardized method to determine SPt and show that SPt,film is reduced compared to SPt,bulk. Boundary and surface scattering reduce the thermodiffusion and the phonon drag contribution to SPt,film by nearly the same factor. We discuss in detail on behalf of a model, which describes the temperature dependence of the absolute Seebeck coefficient, the influence of size effects of electron-phonon and phonon-phonon interaction on SPt. KW - Thin magnetic films PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499007 DO - https://doi.org/10.1063/1.5101028 SN - 0021-8979 VL - 126 SP - 105106 PB - AIP AN - OPUS4-49900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezera, M. A1 - Bonse, Jörn A1 - Römer, G.R.B.E. T1 - Influence of Bulk Temperature on Laser-Induced Periodic Surface Structures on Polycarbonate N2 - In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature. KW - Laser-induced periodic surface structures (LIPSS) KW - Polycarbonate KW - Bulk temperature KW - Ultrashort laser pulses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498242 UR - https://www.mdpi.com/2073-4360/11/12/1947 DO - https://doi.org/https://doi.org/10.3390/polym11121947 SN - 2073-4360 VL - 11 IS - 12 SP - 1947 PB - MDPI CY - Basel, Switzerland AN - OPUS4-49824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rühle, Bastian A1 - Nirmalananthan-Budau, Nithiya A1 - Roloff, Alexander A1 - Resch-Genger, Ute T1 - Surface Functional Group Quantification on Micro- and Nanoparticles N2 - Organic and inorganic micro- and nanoparticles are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. Typically, these applications require further functionalization of the particles with, e.g., antifouling ligands, targeting bioligands, stimuli-responjsive caps, or sensor molecules. Besides serving as an anchor point for subsequent functionalization, the surface chemistry of these particles also fundamentally influences their interaction with the surrounding medium and can have a significant effect on colloidal stability, particle uptake, biodistribution, and particle toxicity in biological systems. Moreover, functional groups enable size control and tuning of the surface during the synthesis of particle systems. For these reasons, a precise knowledge of the chemical nature, the total number of surface groups, and the number of groups on the particle surface that are accessible for further functionalization is highly important. In this contribution, we will will discuss the advantages and limitiations of different approaches to quantify the amount of commonly used surface functional groups such as amino,[1,2] carboxy,[1,2] and aldehyde groups.[3] Preferably, the quantification is carried out using sensitive and fast photometric or fluorometric assays, which can be read out with simple, inexpensive instrumentation and can be validated by complimentary analytic techniques such as ICP-OES and quantitative NMR. T2 - NANAX Hamburg CY - Hamburg, Germany DA - 16.09.2019 KW - Microparticles KW - Nanoparticles KW - Quantitative Analysis KW - Surface KW - Funtional Groups PY - 2019 AN - OPUS4-49616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Quo vadis LIPSS? – Applications of laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 VL - 3/1 SP - 41 EP - 43 PB - Hochschule Mittweida CY - Mittweida AN - OPUS4-49673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. A1 - Kunz, C. A1 - Büttner, T.N. A1 - Naumann, B. A1 - Boehm, A.V. A1 - Gnecco, E. A1 - Bonse, Jörn A1 - Neumann, C. A1 - Turchanin, A. A1 - Müller, F.A. T1 - Large-area fabrication of low- and high-spatial-frequency laser-induced periodic surface structures on carbon fibers N2 - The properties of fiber-reinforced polymers (CFRP) or concretes (ECC) strongly depend on the interface between the fiber and the surrounding matrix. Different methods such as plasma oxidation, chemical or electrolytic etching and chemical vapor deposition have been investigated to increase, for example, the bonding strength. The present study deals with the functionalization of the fiber surface based on laser-induced periodic surface structures (LIPSS). They can be characterized as a modulation of the surface topography on the nano- and microscale that results from the irradiation of the surface with linearly polarized laser radiation close to the ablation threshold. According to their spatial period, LIPSS are classified into low-spatial frequency LIPSS (LSFL) and high-spatial frequency LIPSS (HSFL). The great potential of both types of LIPSS structures regarding functional surface properties was demonstrated in numerous investigations. The objective of the present study was the homogenous manufacturing of both types of LIPSS on large areas of carbon fiber arrangements without damage. The results are discussed based on a detailed analysis of the topographic and chemical surface properties. T2 - 15th International Conference on Laser Ablation (COLA 2019) CY - Hawaii, USA DA - 08.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Carbon fibers KW - Femtosecond laser ablation KW - Surface functionalization PY - 2019 AN - OPUS4-49676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rühle, Bastian A1 - Bresch, Harald A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan A1 - Radnick, Jörg T1 - Perspektive der BAM auf neuartige Materialien N2 - Neuartige Materialien, die bekannte (Werk-)Stoffe mit neuen Funktionalitäten ausstatten, spielen eine zunehmend wichtige Rolle im Bereich der Materialforschung und -prüfung. Das Spektrum neuartiger Materialien reicht von der gezielten Oberflächenfunktionalisierung und -strukturierung makroskopischer Materialien, dünnen Beschichtungen bis hin zu mikro- und nanoskaligen Kompositmaterialien und funktionalen Materialien an der Schnittstelle zur Biologie, Biotechnologie, nachhaltige Energiespeicherung und Sensorik. Dabei bieten neuartige Materialien die Chance, Werkstoffe und Produkte mit erweiterter oder verbesserter Funktionalität zu erhalten und Sicherheit bereits im Designprozess zu berücksichtigen. Durch dieses breite Anwendungsspektrum und die Herausforderungen, die solche Materialien für die Sicherheit in Chemie und Technik mit sich bringen, sind diese in allen Themenfeldern der BAM repräsentiert (Material, Analytical Sciences, Energie, Infrastruktur und Umwelt). Die Aufgaben der BAM erstrecken sich dabei von der Herstellung von Referenzmaterialien für Industrie, Forschung und Regulation, über die Erstellung von standardisierten Referenzverfahren für nachhaltige Messungen im Umwelt- und Lebenswissenschaftsbereich bis hin zur Bereitstellung von belastbaren und zitierbaren Referenzdaten. Durch die genaue Charakterisierung neuartiger Materialien können potentiell problematische Substanzen identifiziert und deren Risiken besser abgeschätzt werden. In diesem Beitrag werden einige aktuelle Beispiele aus diesen Bereichen vorgestellt. T2 - NanoDialog der Bundesregierung - Chancen und Risiken von Neuartigen Materialien CY - Berlin, Germany DA - 22.05.2019 KW - Advanced Materials KW - Nanomaterialien KW - Neuartige Materialien PY - 2019 AN - OPUS4-49594 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Quo vadis LIPSS? – Applications of Laser-Induced Periodic Surface Structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Würth, Christian A1 - Radunz, Sebastian A1 - Frenzel, Florian A1 - Resch-Genger, Ute T1 - Understanding Nucleation and Optical Properties of Upconverting Nanoparticles N2 - Non-linear optical emitters are promising materials for energy applications and biotechnologies. Solid-state multi-band emitters like lanthanide doped up-conversion nanoparticles (UCNPs) show excellent photostability, are excitable in the near infrared (NIR), and show emission bands from the UV to SWIR spectral regions. The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion (ΦUC) and downshifting quantum efficiencies (ΦDS) of these materials, the excitation power dependent population, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We studied the fundamental changes of the luminescence properties of ß-NaYF4 UCNPs doped with Yb3+ and Er3+ depending on size, different surroundings such as aqueous and organic media, and different surface chemistries. We obtained further insights into shelling procedures, FRET optimization, influence of doping concentration, and advantages of different sensitizer ions. T2 - NaNaX CY - Hamburg, Germany DA - 16.09.2019 KW - UpConversion KW - Optical properties KW - Nanoparticle KW - Nanomaterial PY - 2019 AN - OPUS4-49700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meermann, Björn A1 - Wichmann, K. A1 - Lauer, F. A1 - Tremel, W. A1 - Vanhaecke, F. A1 - von der Au, M. A1 - Schwinn, M. A1 - Borovinskaya, O. A1 - Büchel, C. A1 - Kuhlmeier, K. T1 - Neue ICP-MS basierte Methoden zur Analyse von Nano- und Mikropartikeln in der Umwelt N2 - In den vergangen Jahren hat das Umweltbewusstsein in der Bevölkerung stark zugenommen und somit auch das Interesse an der Vermeidung von anthropogenen (Schad-)Stoffen in der Umwelt. Eine (neue) Substanzklasse, deren Umweltauswirkungen noch nicht vollständig untersucht sind und die in den vergangenen Jahren immer mehr an Bedeutung gewonnen hat, sind (metallbasierte) Nanomaterialien. Im Gegensatz zu bspw. Elementspezies weisen Nanomaterialien eine Vielzahl von Eigenschaften auf und lassen sich nicht über nur ein Merkmal beschreiben - dies stellt eine große analytische Herausforderung dar. Hier haben sich vor allem die Feld-Fluss-Fraktionierung (AF4) und die single-particle-ICP-MS als leistungsstarke analytische Methoden herausgestellt. In (aquatischen) Umweltmatrizes (z.B. Oberflächengewässern) liegen neben artifiziellen auch natürliche Partikel vor, was eine weitere große Herausforderung für den Nachweis von Nanomaterialien darstellt. Neben dem Nachweis von anthropogenen Stoffen in der Umwelt ist zudem deren ökotoxikologische Bewertung wichtig. In der aquatischen Ökotoxikologie werden hierzu Testorganismen mit den jeweiligen Substanzen über die Wasserphase exponiert. Effektkonzentrationen (EC50) werden dabei auf Basis der Konzentrationen in der Wasserphase abgeleitet - tatsächlich bioakkumulierte Mengen werden hierbei jedoch meist nicht ermittelt; eine weitere große Herausforderung besteht zudem in der Bewertung von Mischungstoxizitäten. Gängige Testorganismen sind u.a. Kieselalgen (Diatomeen). Diatomeen stehen am Anfang der Nahrungskette - toxikologisch relevante Metalle/Nanomaterialien können sich hierüber im Nahrungsnetz der Oberflächengewässer anreichern und ggf. nachhaltig auswirken. Im ersten Teil des Vortrages werden zunächst neue elementanalytische Methoden zum Nachweis von metallbasierten Nanopartikeln in Umweltmatrizes auf Basis der AF4/ICP-SFMS sowie stabilen Isotopenlabeln am Beispiel von Eisennanopartikeln vorgestellt. Im zweiten Teil wird eine neue elementanalytische Methode als komplementäre Technik zur ökotoxikologischen Bewertung von (Schad-)Stoffen vorgestellt. Die neue Methode basiert auf der on-line Kopplung von HPLC mit der single-cell-ICP-(ToF)-MS (sc-ICP-(ToF)-MS) [1, 3-5]. Hierüber konnten wir erfolgreich die automatisierte Multielementanalytik einzelner Diatomeen realisieren und zur Analyse von mit Metallen inkubierten Diatomeen (cyclotella meneghiniana) einsetzen. Wir konnten zeigen, dass die sc-ICP-ToF-MS zukünftig eine leistungsstarke, komplementäre Technik in der aquatischen Ökotoxikologie zum z.B. Test von Metallen und Nanomaterialien darstellt. T2 - GDCh Wissenschaftsforum Chemie CY - Aachen, Germany DA - 17.09.2019 KW - ICP-MS KW - Nanomaterialien KW - Single particle-ICP-ToF-MS KW - Single cell-ICP-ToF-MS PY - 2019 AN - OPUS4-49743 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meermann, Björn A1 - Faßbender, Sebastian A1 - Rodiouchkina, K. A1 - Vanhaecke, F. A1 - Ley, P. A1 - Metzger, M. A1 - Von der Au, M. A1 - Sturm, M. A1 - Langhammer, N. A1 - Borovinskaya, O. A1 - Büchel, C. A1 - Wichmann, K. A1 - Tremel, W. T1 - New icp-(Tof)-MS based Methods for Material- and Environmental Analysis N2 - Entwicklung von ICP-(ToF)-MS basierten Methoden für die Spezies und Einzelorganismen und -Partikelanalytik an der Schnittstelle Material-Umwelt T2 - Analytisch Chemisches Kolloquium Uni Duisburg-Essen CY - Essen, Germany DA - 04.11.2019 KW - CE-ICP-MS KW - single cell-ICP-ToF-MS KW - single particle-ICP-ToF-MS KW - Speciation analysis PY - 2019 AN - OPUS4-49747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grauel, Bettina A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Haase, M. A1 - Homann, C. T1 - Progress report NaYF4:Yb,Er upconversion nanoparticles: determination of energy loss processes for the systematic enhancement of the luminescence efficiency N2 - A report on the progress of the PhD work on upconversion nanoparticles is given, showing lifetimes and quantum yields of single- and co-doped Yb,Er nanocrystals with and without inert shell. T2 - Arbeitsgruppenseminar Prof. Oliver Benson CY - Berlin, Germany DA - 23.10.2019 KW - Upconversion KW - Spectroscopy KW - Nanoparticles KW - Lifetime PY - 2019 AN - OPUS4-49754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute T1 - Spectral and Lifetime Encoding of Polymer Particles with Cd-free Ternary Semiconductor Nanocrystals for Flow Cytometry with Time Resolved Fluorescence Detection N2 - Multiplexed encoding schemes of nano- and micrometer sized particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. The fluorescence parameter lifetime has been, however, barely exploited. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the excitation and emission wavelength, thus reducing instrument costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically < 10 ns, the fluorescence LTs of ternary semiconductor QDs that represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This present a time region that can be barely covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed and the encoded particles will be then used for fluorescence assays for the analysis of several targets in parallel. Therefor the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs In one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Bad Honnef Physics School Exciting nanostructures: Characterizing advanced confined systems CY - Bad Honnef, Germany DA - 21.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - Seminar CY - Laser-Laboratorium Göttingen e.V., Germany DA - 18.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Electromagnetic radiation KW - Applications KW - Femtosecond laser ablation PY - 2019 AN - OPUS4-49689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kembuan, C. A1 - Saleh, Maysoon I. A1 - Rühle, Bastian A1 - Resch-Genger, Ute A1 - Graf, C. T1 - Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness N2 - A concept for the growth of silica shells with a thickness of 5–250 nm onto oleate-coated NaYF4:Yb3+/Er3+ upconversion nanoparticles (UCNP) is presented. The concept enables the precise adjustment of shell thicknesses for the preparation of thick-shelled nanoparticles for applications in plasmonics and sensing. First, an initial 5–11 nm thick shell is grown onto the UCNPs in a reverse microemulsion. This is followed by a stepwise growth of these particles without a purification step, where in each step equal volumes of tetraethyl orthosilicate and ammonia water are added, while the volumes of cyclohexane and the surfactant Igepal® CO-520 are increased so that the ammonia water and surfactant concentrations remain constant. Hence, the number of micelles stays constant, and their size is increased to accommodate the growing core–shell particles. Consequently, the formation of core-free silica particles is suppressed. When the negative zeta potential of the particles, which continuously decreased during the stepwise growth, falls below −40 mV, the particles can be dispersed in an ammoniacal ethanol solution and grown further by the continuous addition of tetraethyl orthosilicate to a diameter larger than 500 nm. Due to the high colloidal stability, a coalescence of the particles can be suppressed, and single-core particles are obtained. This strategy can be easily transferred to other nanomaterials for the design of plasmonic nanoconstructs and sensor systems. KW - Reverse microemulsion KW - Silica coating KW - Stepwise growth KW - Thick shells KW - Upconversion nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502769 DO - https://doi.org/10.3762/bjnano.10.231 SN - 2190-4286 VL - 10 SP - 2410 EP - 2421 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, M. AN - OPUS4-50276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Nirmalananthan-Budau, Nithiya A1 - Moser, Marko A1 - Roloff, Alexander A1 - Rühle, Bastian A1 - Borcherding, H. A1 - Thiele, T. A1 - Schedler, U. T1 - Cleavable probes and catch and release assays for surface group quantification on 2D- and 3D-supports N2 - Surface functionalization of 2D- and 3D-supports and nanomaterials are nowadays at the core of many applications of functional materials in the life and material sciences. Examples range from membranes and microarrays over bead-based assays, immunoseparation, and next generation sequencing to nanometer-sized optical reporters, nanosensors, and magnetic and optical contrast agents. Typically performed functionalization procedures include silanization and grafting reactions with reactive monomers to introduce functional groups like amino or carboxylic acid groups and the attachment of ligands like polyethylene glycol (PEG) molecules and biomolecules such as peptides, proteins, and DNA.[1-3] We present here a versatile concept to quantify the number of bioanalytically relevant functional groups like carboxyl, amino, and aldehyde moieties through the specific binding and subsequent release of small reporter molecules such as fluorescent dyes and non-fluorescent chromophores utilizing cleavable linkers or the formation of cleavable bonds as a reversible covalent labeling strategy. This is representatively demonstrated for different types of nano- and microparticles with different labeling densities of carboxyl, amino, and aldehyde groups. This strategy enables to separate the signal-generating molecule from the bead surface, thereby circumventing uncertainties associated with light scattering, binding-induced changes in reporter fluorescence, and fluorescence quenching dye-dye interactions on crowded material surfaces.[1-3] Moreover, the reporters are chosen to be detectable with different analytical methods as prerequisite for straightforward validation via method compari-sons and mass balances. Applications of these assays and multimodal cleavable probes range from a quantitative comparison of bead batches and process control to a qualitative prediction of the coupling efficiencies in bioconjugation reactions. T2 - ANAKON 2019 CY - Münster, Germany DA - 25.03.2019 KW - Nanoparticle KW - Surface group KW - Surface analysis KW - Cleavable probe KW - Optical assay KW - Quality assurance KW - Conductometry KW - Dye labeling KW - Methos comparision PY - 2019 AN - OPUS4-47628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Luminescence measurements, calibration strategies and photoluminescence quantum yields N2 - Different types of optical spectroscopies are introduced with special emphasis on method-inherent limitations and reliable instrument calibration and performance validation. In addition, procedures for the determination of spectroscopic key parameters like the photoluminescence quantum yield are presented including required instrument calibrations and material-specific effects related to certain emitters. T2 - Fakultät der University of Ottawa CY - Ottawa, Canada DA - 11.12.2018 KW - Quality assurcance KW - Optical spectroscopy KW - Method comparison KW - Photoluminescence KW - Calibration KW - Performance validation KW - Dye KW - Nanoparticle KW - Quantum dots KW - Quantum yields KW - Uncertainty KW - Method validation PY - 2019 AN - OPUS4-47630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoevelmann, J. A1 - Stawski, T. M. A1 - Besselink, R. A1 - Freeman, H. M. A1 - Dietmann, K. M. A1 - Mayanna, S. A1 - Pauw, Brian Richard A1 - Benning, L. G. T1 - A template-free and low temperature method for the synthesis of mesoporous magnesium phosphate with uniform pore structure and high surface area N2 - Mesoporous phosphates are a group of nanostructured materials with promising applications, particularly in biomedicine and catalysis. However, their controlled synthesis via conventional template-based routes presents a number of challenges and limitations. Here, we show how to synthesize a mesoporous Magnesium phosphate with a high surface area and a well-defined pore structure through thermal decomposition of a crystalline struvite (MgNH4PO4·6H2O) precursor. In a first step, struvite crystals with various morphologies and sizes, ranging from a few micrometers to several millimeters, had been synthesized from supersaturated aqueous solutions (saturation index (SI) between 0.5 and 4) at ambient pressure and temperature conditions. Afterwards, the crystals were thermally treated at 70–250 °C leading to the release of structurally bound water (H2O) and ammonia (NH3). By combining thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM, TEM), N2 sorption analyses and small- and wide-angle X-ray scattering (SAXS/WAXS) we show that this decomposition process results in a pseudomorphic transformation of the original struvite into an amorphous Mg-phosphate. Of particular importance is the fact that the final material is characterized by a very uniform mesoporous structure with 2–5 nm wide pore channels, a large specific surface area of up to 300 m2 g−1 and a total pore volume of up to 0.28 cm3 g−1. Our struvite decomposition method is well controllable and reproducible and can be easily extended to the synthesis of other mesoporous phosphates. In addition, the so produced mesoporous material is a prime candidate for use in biomedical applications considering that Magnesium phosphate is a widely used, non-toxic substance that has already shown excellent biocompatibility and biodegradability. KW - Struvite KW - SAXS KW - Scattering KW - Nanoporous KW - Geology PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477130 DO - https://doi.org/10.1039/c8nr09205b VL - 11 IS - 14 SP - 6939 EP - 6951 PB - Royal Society of Chemistry AN - OPUS4-47713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Molecular dynamics of the asymmetric blend PVME/PS revisited by broadband dielectric and specific heat spectroscopy: Evidence of multiple glassy dynamics N2 - The molecular mobility of the highly asymmetric miscible blend poly(vinyl methyl ether)/polystyrene was investigated by broadband dielectric (frequency range 10^-1 Hz – 10^9 Hz) and specific heat spectroscopy (frequency range 10^1 Hz – 10^4 Hz). The dielectric spectra revealed a complex molecular dynamic behavior, where three different relaxation processes were observed. At temperatures below the glass transition temperature an α´-relaxation was found, with an Arrhenius-like temperature dependence of its relaxation rates. It is assigned to localized fluctuations of the confined PVME segments within a frozen glassy matrix dominated by PS. Above the thermal glass transition temperature two processes with a VFT behavior of their relaxation rates were detected called α1- and α2-relaxation, both originating from PVME dipoles fluctuating in PS-rich environments, however with diverse PS concentrations. The relevant length scales for the processes are assumed to be different, corresponding to the Kuhn segment length for the former relaxation and to the CRR for the latter one. The observed multiple glassy dynamics result from spatial local compositional heterogeneities on a microscopic level. Additionally, SHS investigations were performed for the first time for this system, proving an existence of a fourth relaxation process (α3-relaxation) due to the cooperative fluctuations of both PS and PVME segments. The separation between the thermal α3- and dielectric α2-relaxation increases dramatically with increasing polystyrene concentration, proving that the thermal response is dominated by PS. KW - Polymer blends KW - Dynamic heterogeneity KW - Broadband dielectric spectroscopy KW - Specific heat spectroscopy PY - 2019 DO - https://doi.org/10.1021/acs.macromol.8b02697 SN - 0024-9297 VL - 52 IS - 4 SP - 1620 EP - 1631 PB - ACS Publications AN - OPUS4-47516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Madkour, Sherif T1 - Broadband dielectric spectroscopy on miscible polymer blends in the bulk and in nanometer thick films - Comparison of the different confinement situations N2 - Broadband dielectric spectroscopy in the frequency range from 10-1 to 109 Hz is employed to revisit the segmental dynamics of the miscible blend system poly(vinyl methyl ether)/polystyrene (PVME/PS) in dependence on the composition firstly in the bulk state. Here especially the case of high polystyrene concentrations is considered. It is important to note that only the molecular dynamics of PVME segments as affected by PS is observed because the dipole moment of polystyrene is negligible. Three relaxation processes are found which are due to fluctuations of differently constrained or confined PVME segments. The degree of the confinement of PVME segments due to PS is discussed in dependence on the composition. Further a spatial confinement is considered by investigating thin films of the PVME/PS blend where the film thickness was varied from 100 nm down to 5 nm. Two concentrations of PVME/PS (50/50 wt% and 25/75 wt%) are investigated. To measure nanometer thick films a novel electrode system based on nanostructured electrodes was employed. Nanostructured electrodes can be considered as a cut-edge technology in dielectric spectroscopy. The relaxation spectra of the films showed multiple processes which are discussed in dependence on the film thickness. T2 - Spring Meeting of the American Physical Scociety CY - Boston, Ma, USA DA - 03.03.2019 KW - Polymer blends PY - 2019 AN - OPUS4-47518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yildirim, Arda A1 - Sentker, K. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Huber, P. A1 - Schönhals, Andreas T1 - Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement N2 - The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLC under cylindrical nanoconfinement is studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), where cylindrical nanoconfinement is established through embedding HAT6 into the nanopores of anodic aluminum oxide membranes (AAO), and a silica membrane with pore diameters ranging from 161 nm down to 12 nm. Both unmodified and modified pore walls were considered, and in the latter case the pore walls of AAO membranes were chemical treated with n octadecylphosphonic acid (ODPA) resulting in the formation of a 2.2 nm thick layer of grafted alkyl chains. Phase transition enthalpies decrease with decreasing pore size, indicating that a large proportion of the HAT6 molecules within the pores has a disordered structure, which increases with decreasing pore size for both pore walls. In the case of the ODPA modification the amount of ordered HAT6 is increased compared to the unmodified case. The pore size dependencies of the phase transition temperatures were approximated using the Gibbs Thomson equation, where the estimated surface tension is dependent on the molecular ordering of HAT6 molecules within the pores and upon their surface. DS was employed to investigate the molecular ordering of HAT6 within the nanopores. These investigations revealed that with a pore size of around 38 nm, for the samples with the unmodified pore walls, the molecular ordering changes from planar axial to homeotropic radial. However, the planar axial configuration, which is suitable for electronic applications, can be successfully preserved through ODPA modification for most of the pore sizes. KW - Discotic Liquid Crystals KW - Nanoconfinement PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475222 DO - https://doi.org/10.1039/c8na00308d SN - 2516-0230 VL - 1 IS - 3 SP - 1104 EP - 1116 PB - RSC AN - OPUS4-47522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gramse, G. A1 - Schönhals, Andreas A1 - Kienberger, F. T1 - Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy N2 - We investigate the nearfield dipole mobility of protein membranes in a wide frequency range from 3 kHz to 10 GHz. The results of our nanoscale dielectric images and spectra of bacteriorhodopsin (bR) reveal Debye relaxations with time constants of τ ∼ 2 ns and τ ∼ 100 ns being characteristic of the Dipole moments of the bR retinal and α-helices, respectively. However, the dipole mobility and therefore the protein biophysical function depend critically on the amount of surface water surrounding the protein, and the characteristic mobility in the secondary structure is only observed for humidity levels <30%. Our results have been achieved by adding the frequency as a second fundamental dimension to quantitative dielectric microscopy. The key elements for the success of this advanced technique are the employed heterodyne detection scheme, the broadband electrical signal source, a high frequency optimized cabling, development of calibration procedures and precise finite element modelling. Our study demonstrates the exciting possibilities of broadband dielectric microscopy for the investigation of dynamic processes in cell bioelectricity at the individual molecular level. Furthermore, the technique may shed light on local dynamic processes in related materials science applications like semiconductor Research or nano-electronics. KW - Broadband dielectric microscopy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475230 DO - https://doi.org/10.1039/c8nr05880f SN - 2040-3372 VL - 11 IS - 10 SP - 4303 EP - 4309 PB - RSC AN - OPUS4-47523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tielemann, Christopher A1 - Reinsch, Stefan A1 - Patzig, C. A1 - Höche, T. A1 - Busch, R. T1 - Surface Initiated Microstructure Formation in Glass -Ceramics N2 - Übersicht zur Oberflächeninitiierten Mikrostrukturbildung in Glasoberflächen. Dabei wird auf die Kristallvorzugsorientierung senkrecht zur Oberfläche der sich unter Temperatureinfluss behandelten Glasproben eingegangen. Zudem werden die ersten Experimente zur Eingrenzung des Ursprungs dieser Orientierung vorgestellt. N2 - Overview about the surface initiated microstructure formation in glass surfaces. Samples which are exposed to a temperature treatment, can develop a crystalline microstructure above Tg at the surface. These separated crystals can be preferably oriented towards the surface of the sample. First experiments about the origin of these orientation phenomenon as well as the potentially causing mechanisms are presented and discussed within the presentation. T2 - AK Glasig-kristalline Multifunktionswerkstoffe 2019 CY - TU Clausthal, Germany DA - 21.02.2019 KW - Orientation KW - Glass KW - Crystallization KW - Diopside PY - 2019 AN - OPUS4-47537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, F. A1 - Bente, Klaas A1 - Codutti, A. A1 - Faivre, D. T1 - Using Shape Diversity on the Way to Structure-Function Designs for Magnetic Micropropellers N2 - Synthetic microswimmers mimicking biological movements at the microscale have been developed in recent years. Actuating helical magnetic materials with a homogeneous rotating magnetic field is one of the most widespread techniques for propulsion at the microscale, partly because the actuation strategy revolves around a simple linear relationship between the actuating field frequency and the propeller velocity. However, full control of the swimmers’ motion has remained a challenge. Increasing the controllability of micropropellers is crucial to achieve complex actuation schemes that, in turn, are directly relevant for numerous applications. However, the simplicity of the linear relationship limits the possibilities and flexibilities of swarm control. Using a pool of randomly shaped magnetic microswimmers, we show that the complexity of shape can advantageously be translated into enhanced control. In particular, directional reversal of sorted micropropellers is controlled by the frequency of the actuating field. This directionality change is linked to the balance between magnetic and hydrodynamic forces. We further show an example of how this behavior can experimentally lead to simple and effective sorting of individual swimmers from a group. The ability of these propellers to reverse swimming direction solely by frequency increases the control possibilities and is an example for propeller designs, where the complexity needed for many applications is embedded directly in the propeller geometry rather than external factors such as actuation sequences. KW - Active Matter KW - Low Reynolds number swimmers KW - Actuating materials KW - Microstructure KW - Swarming PY - 2019 DO - https://doi.org/10.1103/PhysRevApplied.11.034039 VL - 11 IS - 3 SP - 034039 PB - American Physical Society AN - OPUS4-47731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinhoff, U. A1 - Hodoroaba, Vasile-Dan T1 - EMPIR Erläuterung der Fördermaßnahme und Beispiele aus der Nanotechnologie N2 - Das EMPIR-Förderprogramm wird kurz erläutert und laufende Projekte aus der Nanotechnologie werden vorgestellt. Der Schwerpunkt liegt auf Standardisierungsprojekten, die gemeinsam mit ISO/TC 229 'Nanotechnologies' und CEN/TC 352 'Nanotechnologies' zu neuen Normen führen sollten. Als Beispiel für laufende Nanotechnologie-Projekte mit Koordination aus Deutschland werden MagNaStand (PTB) und nPSize (BAM) gegeben. T2 - Treffen des Normungsausschusses NA 062-08-17 AA Nanotechnologien CY - KIT, Karlsruhe, Germany DA - 07.03.2019 KW - EMPIR KW - Nanoparticles KW - Reference materials KW - Particle size distribution KW - Traceability KW - Standardisation PY - 2019 AN - OPUS4-47859 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Surface and Microbeam Analytical Methods @BAM N2 - An overview of the activities in the field of surface and microbeam analysis at BAM-6.1 is given with focus on physico-chemical characterization at the nanoscale. Ideas of potential joint activities are presented: structural and chemical analysis of graphene, deposition techniques for nanoparticles, EBSD on steel for a broader range of methods, instruments and types of steel, soft X-ray Analysis of low-Z materials, analysis of mesoporous thin films, etc. T2 - BAM-IFW Workshop CY - Dresden, Germany DA - 28.03.2019 KW - PC characterisation KW - Nanoscale KW - Nanoparticles PY - 2019 AN - OPUS4-47860 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN ED - Bosse, H. ED - Buhr, E. ED - Dziomba, T. ED - Hodoroaba, Vasile-Dan ED - Klein, T. ED - Krumrey, M. T1 - NanoWorkshop 2018: Workshop on Reference Nanomaterials N2 - The Scope of the Workshop was to provide a forum for discussion on progress in development, characterisation and application of reference nanomaterials. Results of recently finsihed national and international research projects have been presented. Moreover, the need for future developments have been addressed. Attendees of teh Workshop were expected to be experts from academia, research institutes, regulatory bodies and industry working or interested in the area of reference nanomaterials. The following structure of Workshop was planned: the main focus of the first day was on reference material needs and development, while teh second day was focussed on reference materials characterisation and standardisation. Over 111 participants frm 13 countries and teh European Joint Research Centre have regsitered for the Workshop with 16 platform presentations and 42 poster contributions grouped in 2 sessions and 10 topical areas. A summary of the observations, analysis and conclusions of the Workshop is made including an overview table of links to information on existing reference nanomaterials. KW - Reference Nanomaterials KW - Nanometrology KW - Standardization KW - Nanoparticle Characterization KW - Comparability of Measurement Results KW - Nanomaterial Properties PY - 2019 SN - 78-3-95606-440-1 DO - https://doi.org/10.7795/110.20190412 SN - 0179-0609 VL - 2018 SP - 1 EP - 315 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig AN - OPUS4-47861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - Chapala, P. A1 - Bermeshev, M. A1 - Pauw, Brian Richard A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Influence of Trimethylsilyl Side Groups on the Molecular Mobility and Charge Transport in Highly Permeable Glassy Polynorbornenes N2 - Superglassy polymers with a large fractional free volume have emerged as novel materials with a broad range of applications, especially in the field of membrane separations. Highly permeable addition-type substituted polynorbornenes with high thermal resistance and chemical stability are among the most promising materials. The major obstacle for extending the practical membrane application is their strong tendency to physical aging, leading to a partial decline in their superior transport performance over time. In the present study, broadband dielectric spectroscopy with complementary X-ray scattering techniques were employed to reveal changes in microporous structure, molecular mobility, and conductivity by systematic comparison of two polynorbornenes with different numbers of trimethylsilyl side groups. Their response upon heating (aging) was compared in terms of structure, dynamics, and charge transport behavior. Furthermore, a detailed analysis of the observed Maxwell−Wagner−Sillars polarization at internal interfaces provides unique information about the microporous structure in the solid films. The knowledge obtained from the experiments will guide and unlock potential in synthesizing addition-type polynorbornenes with versatile properties. KW - Dielectric spectroscopy KW - Molecular mobility KW - Electrical conductivity KW - Gas separation membranes PY - 2019 DO - https://doi.org/10.1021/acsapm.9b00092 SN - 2637-6105 VL - 1 IS - 4 SP - 844 EP - 855 PB - ACS CY - Washington DC AN - OPUS4-47838 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bergstrand, J. A1 - Li, Q. A1 - Huang, B. A1 - Peng, X. A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Zhan, Q. A1 - Widengren, J. A1 - Agren, H. A1 - Liu, H. T1 - On the decay time of upconversion luminescence N2 - In this study, we systematically investigate the decay characteristics of upconversion luminescence (UCL) under anti-Stokes excitation through numerical simulations based on rate-equation models. We find that a UCL decay profile generally involves contributions from the sensitizer’s excited-state lifetime, energy transfer and cross-relaxation processes. It should thus be regarded as the overall temporal response of the whole upconversion system to the excitation function rather than the intrinsic lifetime of the luminescence emitting state. Only under certain conditions, such as when the effective lifetime of the sensitizer’s excited state is significantly shorter than that of the UCL emitting state and of the absence of cross-relaxation processes involving the emitting energy level, the UCL decay time approaches the intrinsic lifetime of the emitting state. Subsequently, Stokes excitation is generally preferred in order to accurately quantify the intrinsic lifetime of the emitting state. However, possible cross-relaxation between doped ions at high doping levels can complicate the decay characteristics of the luminescence and even make the Stokesexcitation approach fail. A strong cross-relaxation process can also account for the power dependence of the decay characteristics of UCL. KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Mechanism KW - Quantum yield KW - Photophysics KW - Lifetime KW - Modeling PY - 2019 DO - https://doi.org/10.1039/c8nr10332a VL - 11 IS - 11 SP - 4959 EP - 4969 PB - RSC Royal Society of Chemistry AN - OPUS4-47888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan T1 - Considerations for nanomaterial identification of powders using volume-specific surface area method N2 - The EC’s recommendation for a definition of nanomaterial (2011/696/EU) should allow the identification of a particulate nanomaterial based on the number-based metric criterion according to which at least 50% of the constituent particles have the smallest dimension between 1 and 100 nm. However, it has been recently demonstrated that the implementation of this definition for regulatory purposes is conditioned by the large deviations between the results obtained by different sizing methods or due to practical reasons such as high costs and time-consuming. For most measurement methods for particle size determination it is necessary to initially disperse the particles in a suitable liquid. However, as the particle size decreases, the adhesion forces increase strongly, making it more difficult to deagglomerate the particles and to assess accurately the result of this process. Therefore, the success of the deagglomeration process substantially determines the measurement uncertainty and hence, the comparability between different methods. Many common methods such as dynamic light scattering (DLS), centrifugal liquid sedimentation (CLS) or ultrasound attenuation spectroscopy (US) can give good comparable results for the size of nanoparticles, if they are properly separated and stabilized (e.g. in reference suspensions). In order to avoid the use of hardly available and expensive methods such as SEM / TEM for all powders, an agglomeration-tolerant screening method is useful. One of the measurement methods well suited to probe the size of particulate powder is the determination of the volume-specific surface area (VSSA) by means of gas adsorption as well as skeletal density. The value of 60 m2/cm3 corresponding to spherical, monodisperse particles with a diameter of 100 nm constitutes the threshold for decisioning if the material is a nano- or non-nanomaterial. The identification of a nanomaterial by VSSA method is accepted by the EU recommendation. However, the application of the VSSA method was associated also with some limitations. The threshold of 60 m2/cm3 is dependent on the particle shape, so that it changes considerably with the number of nano-dimensions, but also with the degree of sphericity of the particles. For particles containing micro-pores or having a microporous coating, false positive results are induced. Furthermore, broad particle size distributions made necessary to additionally correct the threshold. Based on examples of commercially available ceramic powders, the applicability of the VSSA approach was tested in relation with SEM and TEM measurements. The introduction of a correction term for deviations from sphericity and further additions improved the applicability of VSSA as a screening method. T2 - Partec CY - Nuremberg, Germany DA - 09.04.2019 KW - VSSA KW - Nanoparticles PY - 2019 AN - OPUS4-47874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stock, V. A1 - Fahrenson, C. A1 - Voss, L. A1 - Thünemann, Andreas A1 - Boehmert, L. A1 - Sieg, S. A1 - Lampen, A. T1 - Impact of artificial digestion on the sizes and shapes of microplastic particles N2 - The environmental pollution with plastic debris is one of the great challenges scientists are facing in recent times Due to degradation by UV radiation and other environmental factors, larger pieces of plastic can decompose into microscale fragments which can enter human foodstuff through the food chain or by environmental entry Recent publications show a contamination of various food products with microplastic particles suggesting a widespread exposure Thus, orally ingested plastic particles pose a potential health risk to humans In this study, we investigated the impact of artificial digestive juices on the size and shape of the three environmentally relevant microplastic particles polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). T2 - 12th International Particle Toxicology CY - Salzburg , Austria DA - 11.09.2019 KW - Microplastic KW - Particle PY - 2019 AN - OPUS4-48847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saloga, Patrick E. J. A1 - Thünemann, Andreas T1 - Microwave-Assisted Synthesis of Ultrasmall Zinc Oxide Nanoparticles N2 - We report on ultrasmall zinc oxide single-crystalline nanoparticles of narrow size distribution and long-term colloidal stability. These oleate-stabilized nanoparticles were synthesized using microwave-assisted synthesis for 5 min, corresponding to a 99% decrease in synthesis time, when compared to the conventional synthesis method. It was observed that the average particle radius increases from 2.6 ± 0.1 to 3.8 ± 0.1 nm upon increasing synthesis temperature from 125 to 200 °C. This change also corresponded to observed changes in the optical band gap and the fluorescence energy of the particles, from 3.44 ± 0.01 to 3.36 ± 0.01 eV and from 2.20 ± 0.01 to 2.04 ± 0.01 eV, respectively. Small-angle X-ray scattering, dynamic light scattering, and UV–vis and fluorescence spectroscopy were employed for particle characterization. Debye–Scherrer analysis of the X-ray diffraction (XRD) pattern reveals a linear increase of the crystallite size with synthesis temperature. The consideration of the convolution of a Lorentz function with a Gaussian function for data correction of the instrumental peak broadening has a considerable influence on the values for the crystallite size. Williamson–Hall XRD analyses in the form of the uniform deformation model, uniform stress deformation model, and uniform deformation energy density model revealed a substantial increase of strain, stress, and deformation energy density of the crystallites with decreasing size. Exponential and power law models were utilized for quantification of strain, stress, and deformation energy density. KW - SAXS KW - Zinc oxide KW - Microwave synthesis KW - Nanoparticles PY - 2019 DO - https://doi.org/10.1021/acs.langmuir.9b01921 SN - 0743-7463 VL - 35 IS - 38 SP - 12469 EP - 12482 PB - American Chemical Society CY - Washington, D.C., USA AN - OPUS4-49136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - A look inside nanoparticles N2 - Small-angle scattering is the method of choice when it comes to obtaining information about the interior of nanoparticles. The aim is to make nanotechnology safer. While the use of small-angle neutron scattering (SANS) is limited to a few instruments in the world, small-angle X-ray scattering (SAXS) is widely accessible, with an upward trend. The example of core-shell particles shows how simple their analysis is with data from an Anton Paar laboratory system. Here, SAXS is a central tool for the development of new reference materials based on poly(methyl) acrylate-PVDF core-shell particles. The dimensions of the cores and shells can be precisely determined. A detailed analysis makes it possible to show that the cores contain fluorinated and nonfluorinated polymers, whereas the shell consist only of PVDF. This core-shell particles with a diameter around 40 nm show a significantly higher PVDF beta phase content than the PVDF homopolymer when using an emulsion polymerization technique. This finding is of importance with respect to applications in electroactive devices. T2 - SAXS excites: International SAXS Symposium 2019 CY - Graz, Austria DA - 24.09.2019 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoplastics PY - 2019 AN - OPUS4-49126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Moros, M. A1 - Castillo-Michel, H. A1 - Materra, L. A1 - Onorato, G. A1 - Ling, W. L. A1 - Reiss, P. A1 - Tortiglione, C. T1 - In Vivo Biotransformations of Indium Phosphide Quantum Dots Revealed by X‑Ray Microspectroscopy N2 - Many attempts have been made to synthesize cadmium-free quantum dots (QDs), using nontoxic materials, while preserving their unique optical properties. Despite impressive advances, gaps in knowledge of their intracellular fate, persistence, and excretion from the targeted cell or organism still exist, precluding clinical applications. In this study, we used a simple model organism (Hydra vulgaris) presenting a tissue grade of organization to determine the biodistribution of indium phosphide (InP)-based QDs by X-ray fluorescence imaging. By complementing elemental imaging with In L-edge X-ray absorption near edge structure, unique information on in situ chemical speciation was obtained. Unexpectedly, spectral profiles indicated the appearance of In−O species within the first hour post-treatment, suggesting a fast degradation of the InP QD core in vivo, induced mainly by carboxylate groups. Moreover, no significant difference in the behavior of bare core QDs and QDs capped with an inorganic Zn(Se,S) gradient shell was observed. The results paralleled those achieved by treating animals with an equivalent dose of indium salts, confirming the preferred bonding type of In3+ ions in Hydra tissues. In conclusion, by focusing on the chemical identity of indium along a 48 h long journey of QDs in Hydra, we describe a fast degradation process, in the absence of evident toxicity. These data pave the way to new paradigms to be considered in the biocompatibility assessment of QD-based biomedical applications, with greater emphasis on the dynamics of in vivo biotransformations, and suggest strategies to drive the design of future applied materials for nanotechnology-based diagnosis and therapeutics. KW - Indium phosphide KW - Quantum dots KW - Cytotoxicity KW - X-ray microspectroscopy PY - 2019 DO - https://doi.org/10.1021/acsami.9b15433 VL - 11 IS - 39 SP - 35630 EP - 35640 PB - ACS Publications AN - OPUS4-49425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David A1 - Weigert, Florian A1 - Häusler, I. A1 - Carrière, M. A1 - Reiss, P. A1 - Resch-Genger, Ute T1 - Influence of the ZnSe thickness on the photophysical properties of large-size InP/ZnSe/ZnS core-shell QDs N2 - Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior optoelectronic properties and enabled advancements in several key technologies of the 21st century. II-VI QDs containing the heavy metal element cadmium plaid a central role in this research area. Due to the concerns regarding their toxic potential, the European Union will ban cadmium in 2020 from use in any consumer product. Due to their comparable optoelectronic properties and a more environmentally friendly character, indium phosphide based QDs (InP-QDs) are a promising alternative. Their large application potential was already shown in their utilization in the newest commercial TV screens. A vital role for highly luminescent QDs for such an application plays the growth of a surface passivating shell around the InP core. The combination of InP/ZnSe/ZnS in so-called core/shell/shell materials exploits the advantages of a small lattice mismatch (3.3%) between InP and ZnSe and the large band gap of ZnS to efficiently confine the excitons in the core and to increase the overall chemical stability. Using a thin ZnSe layer and a thick ZnS shell has shown to improve the optical properties of InP QDs and only recently, the prevention of blinking and mono-exponential decay kinetics could be achieved with a thick ZnSe Shell. In our contribution, we investigated the influence of the thickness of the intermediate ZnSe layer (1 to 8 monolayers (ML)) on the photophysical properties of InP/ZnSe/ZnS core/shell/shell QDs with a final size of about 10 nm on the ensemble and the single-particle level. By rendering these InP QDs water-soluble, we were able to compare their properties in the organic and aqueous phase and further studied their toxicological potential depending on the chemical composition of their surface shell. T2 - Nanoscience with nanocrystals (NaNaX) 9 CY - Hamburg, Germany DA - 16.09.2019 KW - Indium phosphide KW - Quantum dots KW - Core-shell structures KW - Single-particle measurements PY - 2019 AN - OPUS4-49427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David A1 - Carrière, M. A1 - Reiss, P. T1 - Tuning the photoluminescence of inp quantum dots with gallium N2 - Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior photophysical properties and enabled advancements in several key technologies of the 21st century and numerous technological applications. However, the most studied II-VI semiconductor nanocrystals contain the toxic heavy metal element cadmium, which is limiting their utilization in commercial applications. This has drawn the interest to alternative materials with less toxicity but having similar photophysical features. The newest generation of TV screens based on QDs have shown that there is a promising environmentally friendly alternative with similar optoelectronic properties, namely indium phosphide (InP) QDs. InP QDs possess a bulk band gap of 1.35 eV with an exciton Bohr radius of ca. 10 nm and thus allow to tune their photoluminescence (PL) from the visible to the near-infrared. Tuning the size and shape of InP QDs and thus tailor their optoelectronic properties can be achieved by different strategies, which range from different types and concentrations of precursors, synthesis temperature or post-synthetic manipulations like etching. The incorporation of other elements like Gallium within the InP core synthesis is another possibility. Using a GaP intermediate layer before growing a ZnS shell has been shown to increase the PL quantum yield, which has been attributed to reduced lattice strain and the removal of phosphor vacancies. Different Ga precursors were investigated but a thorough investigation in terms of their reactivity, localization in the QD and influence on the photophysical properties is lacking to date. In this contribution we will present the detailed investigation of the presence of two different Ga precursors within the InP core synthesis. Photophysical characterizations (steady-state and PL life-time measurements), transmission electron microscopy, XRD and EDX gave insights into the reactivity of the Ga precursors, the Ga localization in the InP core and influences on the photophysical properties. The variation of the precursor and surfactant concentration and the utilization of different ligands for the Ga precursor allowed tuning the PL emission towards the blue or the red. Depending on the used precursor type we observed the formation of larger-sized InP/GaP core/shell nanocrystals or the formation of InGaP alloy structures enabling to assess the blue range of emission (475 nm). T2 - Zsigmondy Colloquium CY - Dresden, Germany DA - 10.07.2019 KW - Indium phosphide KW - Quantum dots KW - Gallium doping PY - 2019 AN - OPUS4-49426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute A1 - Wegner, Karl David A1 - Hoffmann, Kristin T1 - Lifetime Barcoding of Polystyrene Beads with Fluorescent Nanocrystals for Fluorescent Lifetime Detection in Flow Cytometry N2 - Multiplexed encoding schemes of nano- and micrometer sized polymer particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the same excitation and emission wavelength, thus reducing instrumental costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically <10ns, the fluorescence LTs of ternary semiconductor QDs which represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This presents a time region that can barely be covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed, and the encoded particles will then be used for fluorescence assays for the analysis of several targets in parallel. Therefore, the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs in one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Tag der Chemie 2019 CY - Berlin, Germany DA - 11.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Pouget, S. A1 - Ling, W. L. A1 - Carriere, M. A1 - Reiss, P. T1 - Gallium – a versatile element for tuning the photoluminescence properties of InP quantum dots N2 - With the goal to tune the emission properties of colloidal InP quantum dots, the incorporation of Ga was explored. Unexpectedly, depending on the nature of the gallium precursor, the photoluminescence shifted either to the red (gallium oleate) or to the blue (gallium acetylacetonate). In the first case, larger-sized InP/GaP core/shell nanocrystals were formed, while in the second case the formation of an InGaP alloy structure enabled the blue range of emission (475 nm) to be accessed. KW - Indium phosphide KW - Quantum dots KW - Gallium doping PY - 2019 DO - https://doi.org/10.1039/C8CC09740B VL - 55 IS - 11 SP - 1663 EP - 1666 PB - Royal Society of Chemistry AN - OPUS4-48306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wegner, Karl David A1 - Dhamo, Lorena A1 - Göhde, W. A1 - Resch-Genger, Ute T1 - Luminescence lifetime encoding for flow cytometry with quantum-dot-encoded beads N2 - Spectral encoding of cells or particles and the discrimination of multiple spectral codes are a critical process in flow cytometry (FCM). Typical issues in spectral encoding are, e.g., the spectral overlap of codes, or the increasing complexity of instruments . The exploitation of the photoluminescence lifetime (LT) as an encoding parameter could be used to circumvent both of these issues, as it adds another dimension to the parameter space, or, when used as a stand-alone parameter, requiring only one excitation light source and one detector. While LT encoding was considered already decades ago it is still not implemented as a routine technique in FCM yet, mainly due to the challenge of very few photons being available within the limited transition time of a cell or particle through the laser spot. Recently, we demonstrated LT-FCM based on luminophores with ns LTs in a compact and low-cost flow cytometer. Measurements on polymer microbeads containing luminophores with distinctly different excited state LTs enabled the complete discrimination of three LT codes and five codes in total could be identified. Now, we have extended our approach towards considerably longer LTs by custom-made polymer microbeads loaded with different ratios of InP/ZnS and AgInS2 quantum dots. The use of these materials significantly expands the usable time range for LT encoding to up to several hundred ns. Our studies demonstrate the possibility to further increase the number of viable LT codes for multiplexing in LT-FCM without the need for extensive hardware modifications. T2 - Visions in Cytometry - 29th Annual Conference of the German Society for Cytometry CY - Berlin, Germany DA - 25.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alam, F. A1 - Wegner, Karl David A1 - Pouget, S. A1 - Amidani, L. A1 - Kvashnina, K. A1 - Aldakov, D. A1 - Reiss, P. T1 - Eu2+: A suitable substituent for Pb2+ in CsPbX3 perovskite nanocrystals? N2 - Eu2+ is used to replace toxic Pb2+ in metal halide perovskite nanocrystals (NCs). The synthesis implies injection of cesium oleate into a solution of europium (II) bromide at an experimentally determined optimum temperature of 130 ○C and a reaction time of 60 s. Structural analysis indicates the formation of spherical CsEuBr3 nanoparticles with a mean size of 43 ± 7 nm. Using EuI2 instead of EuBr2 leads to the formation of 18-nm CsI nanoparticles, while EuCl2 does not show any reaction with cesium oleate forming 80-nm EuCl2 nanoparticles. The obtained CsEuBr3 NCs exhibit bright blue emission at 413 nm (FWHM 30 nm) with a room temperature photoluminescence quantum yield of 39%. The emission originates from the Laporte-allowed 4f7–4f65d1 transition of Eu2+ and shows a PL decay time of 263 ns. The long-term stability of the optical properties is observed, making inorganic lead-free CsEuBr3 NCs promising deep blue emitters for optoelectronics. KW - Perovskite KW - Lead-free KW - fluorescence KW - anion-exchange PY - 2019 DO - https://doi.org/10.1063/1.5126473 SN - 0021-9606 VL - 151 SP - 231101-1 EP - 231101-7 PB - AIP Publishing AN - OPUS4-50696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Musnier, B. A1 - Wegner, Karl David A1 - Comby-Zerbino, C. A1 - Trouillet, V. A1 - Jourdan, M. A1 - Häusler, I. A1 - Antoine, R. A1 - Coll, J.-L. A1 - Resch-Genger, Ute A1 - Le Guevel, X. T1 - High photoluminescence of shortwave infrared-emitting anisotropic surface charged gold nanoclusters N2 - Incorporating anisotropic surface charges on atomically precise gold nanoclusters (Au NCs) led to a strong absorption in the nearinfrared region and could enable the formation of self-assembled Au NCs xhibiting an intense absorption band at ∼1000 nm. This surface modification showed a striking enhancement of the photoluminescence in the Shortwave Infrared (SWIR) region with a quantum yield as high as 6.1% in water. KW - Gold nanoclusters KW - SWIR photoluminescence KW - Self-assembly PY - 2019 DO - https://doi.org/10.1039/C9NR04120F VL - 11 IS - 25 SP - 12092 EP - 12096 PB - Royal Society of Chemistry AN - OPUS4-48305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - The Single Chain Architecture of (Bio)Polymers in Contact with Nanoplastics N2 - In contrast to microplastics, little is known about nanoplastics (1 to 100 nm). In order to make the dectecability of nanoplasics more reliable, we started to develop nanoplastic reference materials. This project also aims to anser the question of how the single chain conformation of bio(polymers) changes in contact with nanoplastics. Small-angle X-ray and neutron scattering methods are suitable methods for studing this topic. Recently the soft and hard interactions between polystyrene nanoplasics and human serum albumin corona was investigated with small-angle neutron scattering. Here we concentrate on small-angle X-ray scattering as our favorite method to study how (bio)polymers change their conformation in contact with nanoplastics. The scattering of bovine serum albumin in its native state can be detected easily. The scattering pattern of this biopolymer changes dramatically when its globular stucture changes to a coil structure. Modeling of chain conformations and the calculation of the scattering pattern is relatively easy to perform. Numerous model calculations will be provided to predict the changes of conformation of single bio(polymer) chains when in conatact with nanoplastics. These predictions will be compared with recent experimenal results from in situ measurments of bio(polymers) in contact with nanoplastics. The impact of temperature, polymer concentration and salt on the single-chain conformation changes will be discussed. T2 - PolyDays 2019 CY - Berlin, Germany DA - 11.09.2019 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Protein KW - Nanoplastics PY - 2019 AN - OPUS4-48959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tarantini, A. A1 - Wegner, Karl David A1 - Dussert, F. A1 - Sarret, G. A1 - Beal, D. A1 - Mattera, L. A1 - Lincheneau, C. A1 - Proux, O. A1 - Truffier-Boutry, D. A1 - Moriscot, C. A1 - Gallet, B. A1 - Jouneau, P.-H. A1 - Reiss, P. A1 - Carriere, M. T1 - Physicochemical alterations and toxicity of InP alloyed quantum dots aged in environmental conditions: A safer by design evaluation N2 - Due to their unique optical properties, quantum dots (QDs) are used in a number of optoelectronic devices and are forecasted to be used in the near future for biomedical applications. The most popular QD composition consists of cadmium selenide (CdSe) or cadmium telluride (CdTe), which has been shown to pose health risks due to the release of toxic cadmium (Cd) ions. Due to similar optical properties but lower intrinsic toxicity, indium phosphide (InP) QDs have been proposed as a safer alternative. Nevertheless, investigations regarding their safety and possible toxicological effects are still in their infancy. The fate and toxicity of seven different water-dispersible indium (In) based QDs, either pristine or after ageing in a climatic chamber, was evaluated. The core of these QDs was composed of indium, zinc and phosphorus (InZnP) or indium, zinc, phosphorus and sulfur (InZnPS). They were assessed either as core-only or as core-shell QDs, for which the core was capped with a shell of zinc, selenium and sulfur (Zn(Se,S)). Their Surface was functionalized using either penicillamine or glutathione. In their pristine form, these QDs showed essentially no cytotoxicity. The particular case of InZnPS QD showed that core-shell QDs were less cytotoxic than core-only QDs. Moreover, surface functionalization with either penicillamine or glutathione did not appreciably influence cytotoxicity but affected QD stability. These QDs did not lead to over-accumulation of reactive oxygen species in exposed cells, or to any oxidative damage to cellular DNA. However, accelerated weathering in a climatic chamber led to QD precipitation and degradation, together with significant cytotoxic effects. Ageing led to dissociation of IneP and ZneS bonds, and to complexation of In Zn ions with carboxylate and/or phosphate moieties. These results show that InZnP and InZnPS alloyed QDs are safer alternatives to CdSe QDs. They underline the necessity to preserve as much as possible the structural integrity of QDs, for instance by developing more robust shells, in order to ensure their safety for future applications. KW - Indium phosphide KW - Safe by design KW - Toxicity KW - EXAFS PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483070 DO - https://doi.org/10.1016/j.impact.2019.100168 VL - 14 SP - 100168-1 EP - 100168-13 PB - Elsevier AN - OPUS4-48307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wegner, Karl David A1 - Dussert, F. A1 - Truffier-Boutry, D. A1 - Benayad, A. A1 - Beal, D. A1 - Mattera, L. A1 - Ling, W. L. A1 - Carrière, M. A1 - Reiss, P. T1 - Influence of the Core/Shell Structure of Indium Phosphide Based Quantum Dots on Their Photostability and Cytotoxicity N2 - With the goal to improve their photostability, InP-based QDs are passivated with three types of inorganic shells, namely (i) a gradient ZnSexS1−x shell, (ii) an additional ZnS shell on top of the gradient shell with two different thicknesses (core/shell/shell, CSS), (iii) an alumina coating on top of ZnS. All three systems have photoluminescence Quantum yields (PLQY) > 50%and similar PL decay times (64–67 ns). To assess their photostability they are incorporated into a transparent poly (methyl methacrylate) (PMMA) matrix and exposed to continuous irradiation with simulated sunlight in a climate chamber. The alumina coated core/shell system exhibits the highest stability in terms of PLQY Retention as well as the lowest shift of the PL maximum and lowest increase of the PL linewidth, followed by the CSS QDs and finally the gradient shell system. By means of XPS studies we identify the degradation of the ZnS outer layer and concomitant xidation of the emissive InZnP core as the main origins of degradation in the gradient structure. These modifications do not occur in the case of the alumina-capped sample, which exhibits excellent chemical stability. The gradient shell and CSS systems could be transferred to the aqueous phase using surface ligand exchange with penicillamine. Cytotoxicity studies on human primary keratinocytes revealed that exposure for 24 h to 6.25–100 nM of QDs did not affect cell viability. However, a trend toward reduced cell proliferation is observed for higher concentrations of gradient shell and CSS QDs with a thin ZnS shell, while CSS QDs with a thicker ZnS shell do not exhibit any impact. KW - Indium phosphide KW - Quantum dots KW - Cytotoxicity KW - Photostability PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494249 DO - https://doi.org/10.3389/fchem.2019.00466 VL - 7 SP - Article Number: 466 PB - Frontiers Media SA AN - OPUS4-49424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - Probenpräparation für AFM-basierte Untersuchungsverfahren N2 - Adapted and advanced sample preparation of semiconductor layer systems with the focused ion beam for AFM-based test methods N2 - Der vorliegende Vortrag gibt einen Überblick über Probenpräparationen mit der Focused Ion Beam (FIB) für AFM-basierte Untersuchungsverfahren. Anhand zweier Beispiele wird gezeigt, wie ionenstrahlpolierte Lamellen aus Halbleiter-Schichtsystemen elektrisch leitfähig auf Substrate platziert werden, so dass in-situ und in-operando Messungen mit Scanning Microwave Microscope (SMM) bzw. Spectroscopic infrared scanning near-field optical microscope (IR-SNOM) durchgeführt werden können. T2 - 15. Berlin-Brandenburger Präparatorentreffen CY - Potsdam/Golm, Germany DA - 11.04.2019 KW - Focused Ion Beam KW - AFM based test methods KW - Sample preparation KW - Semiconductor materials KW - Layer system PY - 2019 AN - OPUS4-47784 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Tchetgnia Ngassam, Ines Leana A1 - Olonade, K. A. A1 - Mbugua, R. A1 - Kühne, Hans-Carsten T1 - Effects and potentials of plant based chemical admixtures on the performance of cementitious construction materials N2 - While today, engineers can choose from a wide range of rheology modifying admixtures, in some parts of the world, these are difficult to access, due to their complex processing. However, alternatives can be bio-based polymers such as polysaccharides from various sources. These are easily accessible all over the world, do not demand for complicated processing, and typically they are more sustainable than many established materials, which are crude oil-based. The paper presents the effects of acacia gum, cassava starch and the gum of triumfetta pendrata A. Rich on the rheological performance of cementitious systems. It is shown that acacia gum can be as efficient as polycarboxylate based superplasticisers, cassava starch can reduce the yield stress slightly with little effect on the plastic viscosity, and the gum of triumfetta pendrata A. Rich increases the thixotropy of cement pastes with plasticizing polymers significantly. T2 - International Conference on Sustainable Materials, Systems and Structures (SMSS 2019) CY - Rovinj, Croatia DA - 20.03.2019 KW - Polysaccharides KW - Rheology KW - Cement KW - Chemical admixtures KW - Bio-based concrete PY - 2019 AN - OPUS4-47675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reimann, C. A1 - Brangsch, J. A1 - Kaufmann, Jan Ole A1 - Adams, L. C. A1 - Onthank, D. C. A1 - Thöne-Reineke, C. A1 - Robinson, S. P. A1 - Hamm, B. A1 - Botnar, R. M. A1 - Makowski, M. R. T1 - Dual-probe molecular MRI for the in vivo characterization of atherosclerosis in a mouse model: Simultaneous assessment of plaque inflammation and extracellular matrix remodeling N2 - Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE−/−) were fed a high-fat-diet (HFD) for up to four-months prior to MRI of the brachiocephalic-artery. To assess response-to-therapy, a statin was administered for the same duration. MR imaging was performed before and after administration of an elastin-specific gadolinium-based and a macrophage-specific iron-oxide-based probe. Following in-vivo MRI, samples were analyzed using histology, immunohistochemistry, inductively-coupled-mass-spectrometry and laser-inductively-coupled-mass-spectrometry. In atherosclerotic-plaques, intraplaque expression of elastic-fibers and inflammatory activity were not directly linked. While the elastin-specific probe demonstrated the highest accumulation in advanced atherosclerotic-plaques after four-months of HFD, the iron-oxide-based probe showed highest accumulation in early atherosclerotic-plaques after two months of HFD. In-vivo measurements for the elastin and iron-oxide-probe were in good agreement with ex-vivo histopathology (Elastica-van-Giesson stain: y = 298.2 + 5.8, R2 = 0.83, p < 0.05; Perls‘ Prussian-blue-stain: y = 834.1 + 0.67, R2 = 0.88, p < 0.05). Contrast-to-noise-ratio (CNR) measurements of the elastin probe were in good agreement with ICP-MS (y = 0.11x-11.3, R² = 0.73, p < 0.05). Late stage atherosclerotic-plaques displayed the strongest increase in both CNR and gadolinium concentration (p < 0.05). The gadolinium probe did not affect the visualization of the iron-oxide-probe and vice versa. This study demonstrates the feasibility of simultaneous assessment of plaque-burden. KW - Gadolinium KW - Elastin KW - Probe KW - Iron oxide KW - Ferumoxytol PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497066 DO - https://doi.org/10.1038/s41598-019-50100-8 VL - 9 SP - 13827 PB - Springer Nature AN - OPUS4-49706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brangsch, J. A1 - Reimann, C. A1 - Kaufmann, Jan Ole A1 - Adams, L. C. A1 - Onthank, D. C. A1 - Thöne-Reinecke, C. A1 - Robinson, S. P. A1 - Buchholz, R. A1 - Karst, U. A1 - Botnar, R. M. A1 - Hamm, B. A1 - Makowski, M. R. T1 - Concurrent Molecular Magnetic Resonance Imaging of Inflammatory Activity and Extracellular Matrix Degradation for the Prediction of Aneurysm Rupture N2 - This study demonstrates the potential of the concurrent assessment of inflammatory activity and ECM degradation by dual-probe molecular MRI in an experimental mouse model of AAA. Based on the combined information from both molecular probes the rupture of AAAs could reliably be predicted, with higher accuracy compared with each probe alone. The combined in vivo quantification of these biomarkers in 1 imaging session may be useful to improve the in vivo characterization of AAAs. KW - Aneurism KW - Extracellular matrix KW - Inflammation KW - Macrophage KW - Magnetic resonance imaging PY - 2019 DO - https://doi.org/10.1161/CIRCIMAGING.118.008707 VL - 12 IS - 3 SP - e008707 PB - American Heart Association, Inc. CY - Waltham, MA, USA AN - OPUS4-49705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Le Xuan, Hoa T1 - Gezieltes Crosslinking von Immunglobulinen mit ortspezifischen Bindern N2 - Die neue Crosslinking-Methode ist hilfreich, um Immunglobuline des Isotyps G ortspezifisch an ihrer Bindungsstelle mit Protein A oder G zu konjugieren. Die Kopplungen von Protein A und G konnten erfolgreich an Maus- und Human-IgG durchgeführt, sowie die Bedingungen untersucht und optimiert werden. Die Aktivierung von Protein G mit Glutaraldehyd erfolgt am besten bei pH 8 und die anschließende Kopplung mit Maus-IgG1 bei einem pH-Wert von 6. Jedoch wurden mit SIAB und Sulfo-SIAB als Crosslinker im Vergleich zu Glutaraldehyd noch höhere Signale erhalten. Für die Kopplung von SIAB sind 40% DMSO im Reaktionspuffer günstig, währenddessen Sulfo-SIAB gut wasserlöslich ist daher keine Lösungsvermittler benötigt. Es ergab sich ein optimaler pH-Wert von 7,4 um Protein A mit SIAB zu aktivieren und den gleichen pH-Wert um die Kopplung mit Maus-IgG1 durchzuführen. Für die Kopplung von Protein G mit Maus-IgG1 hingegen zeigten die Experimente, dass ein leicht saurer pH-Wert bei pH 6 für den IgG-Kopplungsschritt am günstigsten ist. Während die Inkubationszeit von Maus-IgG1 mit Protein G bei 16 h liegt, muss mit Protein A bis zu 40 h inkubiert werden, um das Kopplungsmaximum zu erreichen. Des Weiteren wurde das Crosslinking von Human-IgG (Herceptin) mit SIAB untersucht. Dabei zeigte sich, wie in der Abbildung 47 zu sehen ist, dass Protein A und G vergleichbar gut an Human-IgG zu koppeln sind. Für das Crosslinking von Protein G mit Maus-IgG1 ist dagegen ein deutlich besserer Umsatz im Vergleich zu Protein A zu erkennen (Abbildung 48). Heterobifunktionale Linker können mit der reaktiveren Gruppe die erste Bindung eingehen, um erst nach Zugabe eines weiteren Reagenzes die zweite Bindung auszubilden und zudem intramolekulare Reaktionen möglichst zu vermeiden. KW - Antikörper KW - Antibodies KW - Vernetzung KW - Immobilisierung KW - Immobilization KW - Herceptin KW - Human antibodies KW - Therapeutic antibodies KW - Diagnostic antibodies KW - Oriented immobilization PY - 2019 SP - 1 EP - 100 PB - Humboldt-Universität zu Berlin CY - Berlin AN - OPUS4-54658 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Juds, Carmen T1 - Biocombinatorially selected peptide-polymer conjugates as polypropylene binders N2 - Peptide-polymer bioconjugates combine oligopeptides with synthetic polymer blocks and can be used for various applications in material sciences. In recent years, bioconjugates were applied as compatibilizers and coatings. Biocombinatorial approaches, such as phage display, have been shown to yield strong binding peptides, which exhibit excellent coating properties as peptide-PEO conjugates. Phage display represents a widely exploited strategy to select peptides or proteins that exhibit highly specific affinity to various substrates. Following a phage display experiment, DNA sequencing of binding phage clones is required in order to get the sequence information of the binding peptides. Traditionally, random clone picking followed by Sanger sequencing was applied. However, this method may not necessarily identify the strongest binding clones. Next-generation sequencing made sequencing of whole phage libraries possible, which highly improved the selection of strong binders. Here, we show that the biocombinatorial method of phage display combined with next generation DNA sequencing of whole phage libraries represents a powerful tool for an application in material chemistry. Phage display is used to find specific target binding peptides for polypropylene surfaces (PP). PP binders are of particular interest because thus far gluing or printing on PP is challenging due to its low surface energy. Scripts for sequence data analysis were developed and promising sequences were synthesized as peptide-PEO conjugates. Fluorescence based adsorption experiments on PP surfaces led to the identification of strong binding sequences and a better understanding of the peptide-surface interactions. T2 - 257th National Meeting of the American-Chemical-Society (ACS) CY - Orlando, FL, USA DA - 31.03.2019 KW - Peptides KW - Surfaces KW - Phage Display KW - Peptide Library KW - Screening KW - Glue KW - Paint KW - Polyethylene Glycol KW - PEG KW - Next Generation Sequencing PY - 2019 AN - OPUS4-48837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Hodoroaba, Vasile-Dan A1 - Braun, Ulrike A1 - Pfeifer, Dietmar A1 - Sturm, Heinz T1 - Reinforced UV curable cycloaliphatic epoxy oligosiloxane resin nanocomposite for coating applications N2 - Coating materials are nowadays often required to deliver not only sufficient barrier performance and suited optical appearance but a broad range of other functional properties. The incorporation of inorganic nanoparticles (NPs) is known to improve many key characteristics and provide new functionalities in polymer materials. Presented work aims to prepare and characterize an organic-inorganic coating material designed to bring together advantageous properties of hybrid materials and reinforcement effect delivered from the inorganic NPs embedment. Siloxane-based hybrid resins hold great advantages as coating materials as their properties can be tuned between those of polymers and those of glasses, thus, the compositions with superior thermal and mechanical properties can be achieved. We used Cycloaliphatic Epoxy Oligosiloxane (CEOS) resin as a polymeric matrix where the network formation was achieved by UV induced cationic polymerisation. Boehmite Alumina (BA) nanoparticles were added to CEOS resin as a reinforcing agent and resultant material was processed into films either by bar-coating or by spin-coating depending on further characterization procedure. Two different types of BA NPs, hydrophilic and organophilic, were used in order to assess the impact of particles surface on the resin characteristics. CEOS synthesis by condensation reaction was confirmed using 13C and 29Si NMR. Changes in CEOS photocuring process, resulting from particles incorporation, were monitored by real-time IR spectroscopy. At the same time, the thermal behaviour was evaluated by DSC and TGA methods. Morphology of the coatings was investigated by means of SEM operated in transmission mode. It was observed that BA presence increased the epoxy conversion degree and glass transition temperature. Material formulations providing best film characteristics were determined with regard to the particle type and loading. Compared to the hydrophilic nanoparticles, organophilic BA NPs yield superior overall performance of the foils. T2 - HYMA Conference CY - Sitges, Spain DA - 11.03.2019 KW - Cycloalyphatic epoxy oligosiloxane KW - Nanocomposite KW - Boehmite KW - Photocuring PY - 2019 AN - OPUS4-47641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Topolniak, Ievgeniia A1 - Ghasem Zadeh Khorasani, Media A1 - Hodoroaba, Vasile-Dan A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Versatile role of boehmite particles in epoxy-based nanocomposites N2 - Thermosetting materials are gaining increasing attention in many structural composite applications. However, the incorporation of inorganic nanoparticles (NPs) into polymer matrix is a promising approach to enhance their functional characteristics, and thus, to enable the development of thermosets advanced application. It has been shown that Boehmite Alumina (BA) used as nanofillers can improve different parameters of polymers. This NPs can be easily tailored enabling desirable interactions with a big range of polymers. However, the overall effect of nanofiller depends on many factors, therefore, making it hard to predict the resulted performance of nanocomposites. In the current contribution we would like to discuss the impact of Boehmite NPs on two different epoxy resin nanocomposite systems with the focus on the possible influence mechanisms of this nanofiller. As the first system, UV curable Cycloaliphatic-Epoxy Oligosiloxane (CEOS) resin/Boehmite nanocomposites were investigated by FTIR, TGA, DSC and T-SEM. It was observed that incorporation of BA leads to the reinforcement of glass transition (Tg) and overall thermal stability indicating the attractive interactions between BA and CEOS network. In addition, an increase in epoxy conversion of CEOS was concluded for nanocomposites assuming that particles are involved in UV polymerisation processes. The second epoxy/Boehmite nanocomposite is based on the bisphenol-A-diglycidyl ether (DGEBA) cured with methyl tetrahydrophtalic acid anhydride (MTHPA). Thermomechanical as well as nanomechanical properties of this material were investigated by DMTA and IR spectroscopy and the advanced Intermodulation AFM, respectively. In contrast to the first system, it was found that BA leads to a decrease of Tg and crosslink density of the polymer while the young’s modulus of the composite and local stiffness of polymer matrix increase significantly. As a result, the versatile role of Boehmite was detected depending on the investigated systems. Based on the obtained results, the parameters indicating property-efficient epoxy/Boehmite system are suggested. T2 - HYMA Conference CY - Sitges, Spain DA - 11.03.2019 KW - Epoxy KW - Boehmite KW - Curing KW - Nanocomposite PY - 2019 AN - OPUS4-47640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Zutta Villate, Julian Mateo T1 - Radioactive gold nanoparticles for cancer treatment: Size and cluster dependent damage studied by Geant4 Monte-Carlo simulations N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive ¹⁹⁸Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply ¹⁹⁸AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. KW - Gold Nanoparticles KW - AuNP KW - Radioactive decay KW - Beta decay KW - DNA KW - DNA damage KW - Radiation damage KW - MCS KW - Monte-Carlo simulation KW - Geant4 KW - Dosimetry KW - Microdosimetry KW - Cancer treatment KW - Radiationtherapy KW - Brachytherapy KW - OH radicals KW - LEE KW - low energy electrons KW - gamma ray KW - beta particle KW - radiolysis KW - clustered nanoparticles KW - NP KW - Simulation KW - particle scattering KW - Geant4-DNA KW - Energy deposit PY - 2019 DO - https://doi.org/10.1140/epjd/e2019-90707-x SN - 1434-6060 SN - 1434-6079 VL - 73 IS - 5 SP - 95, 1 EP - 7 PB - Springer CY - Berlin Heidelberg AN - OPUS4-47952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee T1 - Grenzflächen als Material: Konzepte und Beispiele zu nanoverstärkten Duroplasten N2 - Nachdem Jahrzehnte die Grenzfläche zwischen Kohlefaser und Duroplastmatrix optimiert wurde liegt das Augenmerk heute auf der Polymermatrix selbst. Diese lässt sich hinsichtlich ihres Elastizitätsmoduls und ihrer Bruchfestigkeit verbessern, indem Nanopartikel aus Böhmit (AlOOH) eindispergiert werden. Der Vortrag geht auf integrale und hochauflösend-bildgebende Methoden ein die ein Verständnis der komplexen Zusammenhänge ermöglichen. Nach einer chemischen in-situ Analyse des Aushärtvorgangs, aus welchem sich die Bedeutung der externer Parameter ablesen lässt, werden diverse hochauflösende, neue Methoden der Rasterkraftmikroskopie (AFM) eingeführt. Der lokalen Bestimmung des E-Moduls der Nanopartikel folgen Ausführungen zum temperaturabhängigen Chemismus des Böhmits, der während der Aushärtung Wasser freisetzt. Die hochauflösende Bestimmung der Oberflächenpotentiale, der Steifigkeit, der attraktiven Kräfte zwischen Spitze und Probe sowie der Energiedissipation im Kontakt stellen auf der Nanoskala eine komplexe Datenquelle dar, die auf der Makroskala einer Ergänzung bedarf: Durch Kombination von dynamisch-mechanisch-thermischer Analyse einerseits und Kartierung physikalischer Eigenschaften auf der Nanoskala andererseits kann der Zusammenhang zwischen chemischer Steuerung der Netzwerkbildung und den mechanischen Eigenschaften des Nanokomposits geklärt werden. Überraschend ist, dass bei geeigneter Steuerung der lokale E-Modul der Polymermatrix den des Füllstoffs übersteigt. Die Rissfortschrittsenergie wird in Böhmit-modifiziertem Epoxy verbessert absorbiert, die These dazu ist, dass die (010)-Gleitebenen, die nur durch Wasserstoffbrücken zusammen gehalten werden, einigermaßen schadlos geschert werden können. Daraus folgt, dass das System auf der Nanoskala über einen, wenn auch begrenzten, Selbstheilmechanismus verfügt. Zudem wird durch die hohe Heterogenität der Steifigkeit und Energiedissipation des Nanokomposits eine Risstrajektorie vielfach umgelenkt und somit früher gestoppt. Ergebnisse dieses Vortrags stammen aus einer Zusammenarbeit innerhalb des DFG-Forscherverbundes FOR2021 „Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtbau“. T2 - Niedersächsisches Symposium Materialtechnik - NSM 2019 CY - Clausthal, Germany DA - 14.02.1019 KW - Nanokomposit KW - Böhmit KW - Risstrajektorie KW - Oberflächenpotential KW - Energiedissipation im Kontakt KW - Oberflächensteifigkeit KW - attraktive Wechelwirkung KW - Epoxy-Anhydrid Duroplast KW - Leichtbau PY - 2019 AN - OPUS4-47636 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dudziak, Mateusz A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Thermal properties of polymer nanocomposites based on polycarbonate (PC) and boehmite N2 - Nanocomposites are extremely versatile due to their physicochemical properties, which differ significantly from bulk homopolymers. One of the inorganic nanomaterials which are increasingly used as a filler in polymer matrices is boehmite, typically used as an inexpensive flame retardant. Here, it is used as a nanofiller in polycarbonate and polyamide, expecting to improve their mechanical properties. For industrial use boehmite is obtained by the solvothermal method, resulting in a layered nanomaterial, whereas naturally it occurs as single crystals with the size of <100µm. In this work we are obtaining and isolating boehmite crystals by a bottom-up method, in which a reaction between aluminum nitride and sodium hydroxide. Obtaining boehmite as microcrystals is necessary for its analysis and characterization, as well as to investigate its interaction with polymer matrices at the polymer/particle interface. Here, the obtained particles in polymer matrices are characterized with differential scanning calorimetry and thermogravimetry analysis. T2 - 6th International Conference on Multifunctional, Hybrid and Nanomaterials CY - Sitges, Spain DA - 11.03.2019 KW - Boehmite KW - Polycarbonate PY - 2019 AN - OPUS4-47769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dudziak, Mateusz A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Thermal properties of polymer nanocomposites based on polycarbonate (PC) and boehmite N2 - Nanocomposites are extremely versatile due to their physicochemical properties, which differ significantly from bulk homopolymers. One of the inorganic nanomaterials which are increasingly used as a filler in polymer matrices is boehmite, typically used as an inexpensive flame retardant. Here, it is used as a nanofiller in polycarbonate and polyamide, expecting to improve their mechanical properties. For industrial use boehmite is obtained by the solvothermal method, resulting in a layered nanomaterial, whereas naturally it occurs as single crystals with the size of <100µm. In this work we are obtaining and isolating boehmite crystals by a bottom-up method, in which a reaction between aluminum nitride and sodium hydroxide. Obtaining boehmite as microcrystals is necessary for its analysis and characterization, as well as to investigate its interaction with polymer matrices at the polymer/particle interface. Here, the obtained particles in polymer matrices are characterized with differential scanning calorimetry and thermogravimetry analysis. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 31.03.2019 KW - Boehmite KW - Polycarbonate PY - 2019 AN - OPUS4-47768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zutta Villate, J. M. A1 - Hahn, Marc Benjamin T1 - Radioactive gold nanoparticles for cancer treatment N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. KW - Gold KW - Nanoparticle KW - Cancer KW - Monte-Carlo KW - Simulation KW - Cluster PY - 2019 DO - https://doi.org/10.1140/epjd/e2019-90707-x SN - 1434-6060 SN - 1434-6079 VL - 73 IS - 95 SP - 1 EP - 7 PB - Springer CY - Berlin AN - OPUS4-47964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau-Lifshitz equation N2 - The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - Magnetic nanoparticles KW - Stochastic Landau Lifshitz Gilbert equation KW - Magnetic moment KW - Landau Lifshitz equation KW - Exchange interaction KW - OOMMF KW - Object oriented micromagnetic framework KW - Temeprature scaling KW - LLG KW - Ferromagnetism KW - Micromagnetism PY - 2019 AN - OPUS4-48762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Zutta Villate, J. M. T1 - Radioactive gold nanoparticles for cancer treatment: Size and cluster dependent damage studied by Geant4 Monte-Carlo simulations N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive ¹⁹⁸Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply ¹⁹⁸AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - DNA KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - MCS KW - Nanoparticle KW - AuNP KW - Gold Nanoparticle KW - low energy electrons KW - LEE KW - OH radicals KW - particle scattering KW - Radiationtherapy KW - Radioactive decay KW - Monte-Carlo simulation KW - Energy deposit KW - DNA damage PY - 2019 AN - OPUS4-48763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Ghasem Zadeh Khorasani, Media A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Water as side effect of reinforcing boehmite filler Local changes in anhydride cured epoxy resin N2 - Nanocomposites offer wide opportunities for lightweight constructions and enable reduction of weight and volume. Beside macroscopic toughening nanoparticle reinforced polymers show a soft interface around boehmite (AlOOH) filler nanoparticles. A related strong interaction between boehmite and the anhydride cured resin system is widely suspected in literature but not determined by structural Analysis. Determination of the molecular structure is important to allow simulations approaching the real system and predict future reinforcing effects. DRIFT (diffuse refletance infrared fourier transformed) spectra of the boehmite reinforced anhydride cured epoxy show significant changes in the molecular structure compared to the neat polymer. Further investigations of the interactions between the single components of the resin system and the boehmite filler pointed out reactions between released water released from the boehmite filler and the anhydride hardener or amine accelerator. This leads to the discussion of competing polymerisation mechanisms that highly influence the polymer properties. Ongoing experiments and literature research approve that this impact of water is able to locally change the stoichiometrie, alter the curing mechanism or support an inhomogeneous crosslink density. T2 - Polydays 2019 CY - Erwin-Schrödinger-Zentrum, Berlin Adlershof, Germany DA - 11.09.2019 KW - Nanocomposites KW - Epoxy KW - FTIR spectroscopy KW - Boehmite alumina PY - 2019 AN - OPUS4-49010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard A1 - Topolniak, Ievgeniia A1 - Schenderlein, Matthias A1 - Sturm, Heinz T1 - Nano polymer (composite) printing N2 - This talk introduces the PolyPoly, a new device at BAM which enables the three-dimensional structuring of polymer nanocomposites with an extremely high resolution of 150x150x600 nm. Initial examples and findings will be shown. T2 - BAM-IFW Workshop CY - Dresden, Germany DA - 28.03.2019 KW - Multiphoton laser structuring KW - Polymer nanocomposites KW - 3d structuring KW - Additive manufacturing PY - 2019 AN - OPUS4-48041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Harald A1 - Rühle, Bastian A1 - Hodoroaba, Vasile-Dan A1 - Seeger, Stefan A1 - Resch-Genger, Ute A1 - Braun, Ulrike A1 - Jann, Oliver A1 - Wilke, Olaf A1 - Geißler, Daniel A1 - Schmidt, Alexandra A1 - Unger, Wolfgang A1 - Sturm, Heinz T1 - Stand der Aktivitäten zur gemeinsamen Forschungsstrategie N2 - Die gemeinsame Forschungsstrategie der Bundesoberbehörden zur Nanotechnologie wurde 2016 veröffentlicht. Die darin enthaltenen Aufgaben wurden von den Bundesoberbehörden vielfältig bearbeitet. Diese Präsentation gibt einen Überblick über die Projekte, die von der BAM bis 2019 bearbeitet wurden/werden und sich in den Rahmen der Forschungsstrategie einordnen. T2 - Workshop zur gemeinsamen Forschungsstrategie der Bundesoberbehörden „Nanomaterialien und andere innovative Werkstoffe: anwendungssicher und umweltverträglich“ CY - Berlin, Germany DA - 02.09.2019 KW - Nano KW - Bundesoberbehörden KW - Forschungsstrategie KW - Nanomaterialien KW - Nanotechnologie PY - 2019 AN - OPUS4-49586 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Simulational tools in nanoparticle research: Micromagnetics and particle scattering N2 - Simulational tools are applied to investigate the physical properties of nanoparticles. For the description of radioactive gold nanoparticles, particles scattering simulations are performed with the Geant4 monte carlo simulation toolkit. The temperature dependent behaviour of the magnetization dynamics of different magnetic nanoparticles are simulated with the object oriented micormagnetic framework (OOMMF). T2 - NanoBioAp CY - LLanes, Spain DA - 23.05.2019 KW - Monte Carlo KW - Monte-Carlo simulation KW - MCS KW - Nanoparticle KW - AuNP KW - Dosimetry KW - Radioactive NP KW - Microdosimetry KW - Geant4 KW - OOMMF KW - Micromagnetism KW - Simulation KW - Magnetic nanoparticle KW - LLG PY - 2019 AN - OPUS4-48110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghasem Zadeh Khorasani, Media A1 - Elert, Anna Maria A1 - Hodoroaba, Vasile-Dan A1 - Agudo Jácome, Leonardo A1 - Altmann, Korinna A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Short- and long-range mechanical and chemical interphases caused by interaction of Boehmite (γ-AlOOH) with anhydride-cured epoxy resins N2 - Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands. KW - Nanocomposites KW - Interphase KW - Intermodulation AFM KW - Electron microscopy KW - Infrared nano AFM PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483672 UR - https://www.mdpi.com/2079-4991/9/6/853/htm DO - https://doi.org/10.3390/nano9060853 SN - 2079-4991 VL - 9 IS - 6 SP - 853, 1 EP - 20 PB - MDPI AN - OPUS4-48367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Zarinwall, A. A1 - Silbernagl, Dorothee A1 - Garnweitner, G. A1 - Sturm, Heinz T1 - Mechanical coupling of matrix and nanoparticles depending on particle surface modification N2 - Boehmite nanoparticles has been successfully functionalized with APTES. After APTES functionalization further modification with tailored molecules e.g. via carboxylic acids is possible. The tailored surface functionalization is strongly enhanced by improved coupling protocols. Arbitrary variation of the functionalization degree is possible. Thereby the temperature stable APTES functionalization enables a wide range of functional groups. By TGA-MS analysis strong evidence for the bonding situation of the APTES on the boehmite surface has been found. Additionally first experiments has been performed to predict the polymer-particle compatibility enhancement via reverse wetting angle measurements with AFM. T2 - Workshop Acting Principles of Nano-Scaled Matrix Additives for Composite Structures CY - BAM, Berlin, Germany DA - 11.10.2019 KW - Surface modification KW - Nanocomposites KW - Boehmite KW - Silane KW - Thermogravimetry KW - Mass spectrometry PY - 2019 AN - OPUS4-49435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Braun, Ulrike T1 - Kunststoffe und deren Recycling – Materialwissenschaftliche Erkenntnisse, um mehr Recyclat einzusetzen N2 - Nach einer Übersicht zu den immer schneller aktualisierenden Rahmenbedingungen von Politik und Gesellschaft folgt eine Übersicht zu materialwissenschaftlichen Problemen des Recyclings von Kunststoffen. Lösungsansätze aus der Forschung reichen von einfacher Optimierung bis hin zur radikalen Neukonstruktion der polymeren Werkstoffe. Aus dem bereits möglichen Ansatz "performance-by-design" wird ein neuer Weg des "recycling-by-design" adressiert. Dies inkludiert methodisch eine skalenübergreifende Modellierung und die Depolarisation bis zum Monomer. T2 - Gefahrgut-Technik-Tage CY - Berlin, Germany DA - 07.11.2019 KW - Recycling KW - Kunststoff KW - Additiv KW - Polymer KW - Normung KW - Plastikstrategie KW - Grenzfläche als Material KW - Recycling-by-design PY - 2019 AN - OPUS4-49561 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bakenecker, A. A1 - Topolniak, Ievgeniia A1 - Lüdtke-Buzug, K. A1 - Pauw, Brian Richard A1 - Buzug, T. T1 - Additive manufacturing of superparamagnetic micro-devices for magnetic actuation N2 - 3D microstructures with sub-micron resolution can be manufactured in additive manner applying multi-photon laser structuring technique. This paper is focused on the incorporation of superparamagnetic iron oxide nanoparticles into the photoresist in order to manufacture micrometer-sized devices featuring a magnetic moment. The aim of the project is to achieve untethered actuation of the presented objects through externally applied magnetic fields. Future medical application scenarios such as drug delivery and tissue engineering are targeted by this research. T2 - Additive Manufacturing Meets Medicine 2019 CY - Lübeck, Germany DA - 12.09.2019 KW - MPI KW - Two-Photon Polymerization KW - Magnetic swimmers KW - MPLS PY - 2019 UR - www.journals.infinite-science.de/ammm DO - https://doi.org/10.18416/AMMM.2019.1909S09T06 SP - 153 EP - 154 PB - Infinite Science Publishing AN - OPUS4-49114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -