TY - CONF
A1 - Krüger, Jörg
T1 - Unerwünschte Röntgenemission bei der UKP-Lasermaterialbearbeitung
N2 - Der Vortrag fasst aktuelle Aspekte zum unerwünschten Auftreten von Röntgenstrahlung bei der Ultrakurzpuls-Lasermaterialbearbeitung zusammen. Es werden Einflussparameter, Grenzwerte, Schutzmaßnahmen, Fragen der Abschirmung und rechtliche Gesichtspunkte diskutiert.
T2 - Bayerische Laserschutztage 2022
CY - Online meeting
DA - 18.01.2022
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
PY - 2022
AN - OPUS4-54259
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, C.
A1 - Feiler, Torvid
A1 - Heilmann, Maria
A1 - Braga, D.
A1 - Emmerling, Franziska
A1 - Grepioni, F.
T1 - Too much water? Not enough? In situ monitoring of the mechanochemical reaction of copper salts with dicyandiamide
N2 - n situ monitoring of mechanochemical reactions between dicyandiamide (DCD) and CuX2 salts (X = Cl−, NO3−), for the preparation of compounds of agrochemical interest, showed the appearance of a number of phases. It is demonstrated that milling conditions, such as the amount of water added in wet grinding and/or the milling frequency, may affect the course of the mechanochemical reactions, and drive the reaction towards the formation of different products. It has been possible to discover by in situ monitored experiments two novel crystalline forms, namely the neutral complexes [Cu(DCD)2(OH2)2(NO3)2] (2) and [Cu(DCD)2(OH2)Cl2]·H2O (4), in addition to the previously known molecular salt [Cu(DCD)2(OH2)2][NO3]2·2H2O (1, DIVWAG) and neutral complex [Cu(DCD)2(OH2)Cl2] (3, AQCYCU), for which no synthesis conditions were available. Compounds 2 and 4 were fully characterized via a combination of solid-state techniques, including X-ray diffraction, Raman spectroscopy and TGA.
KW - Mechanochemistry
KW - In situ
PY - 2022
DO - https://doi.org/10.1039/d1ce01670a
VL - 24
IS - 6
SP - 1292
EP - 1298
PB - RSC
AN - OPUS4-54344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Tothadi, S.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Different mechanical responses of dimorphic forms of Anthracene Schiffbase crystal
N2 - We obtained concomitant dimorphic forms of Anthracene Schiffbase (N-(anthracen-9-yl methylene)-2,5- dichloroaniline) from hexane solvent. Two polymorphs can be differentiated by their morphology and mechanical properties. One form is long acicular type and elastically bendable while another form is block shaped and brittle in nature. Mechanical property is attributed to underlying crystal packing. Hirsh- feld analysis and energy framework calculations were done to corroborate structure-property correlation of two forms.
KW - Elasticity
KW - Mechanical properties
KW - Anthracene schiff base
KW - Dimorphs
PY - 2021
DO - https://doi.org/10.1016/j.molstruc.2021.132182
VL - 1252
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-54356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chinnasamy, R.
A1 - Ravi, J.
A1 - Pradeep, V.V.
A1 - Manoharan, D.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Adaptable Optical Microwaveguides From Mechanically Flexible Crystalline Materials
N2 - Flexible organic crystals (elastic and plastic) are important materials for optical waveguides, tunable optoelectronic devices, and photonic integrated circuits. Here, we present highly elastic organic crystals of a Schiff base, 1-((E)-(2,5-dichlorophenylimino)methyl)naphthalen-2-ol (1), and an azine molecule, 2,4-dibromo-6-((E)-((E)-(2,6-dichlorobenzylidene)hydrazono)methyl)phenol (2). These microcrystals are highly flexible under external mechanical force, both in the macroscopic and the microscopic regimes. The mechanical flexibility of these crystals arises as a result of weak and dispersive C−H⋅⋅⋅Cl, Cl⋅⋅⋅Cl, Br⋅⋅⋅Br, and π⋅⋅⋅π stacking interactions. Singly and doubly-bent geometries were achieved from their straight shape by a micromechanical approach using the AFM cantilever tip. Crystals of molecules 1 and 2 display a bright-green and red fluorescence (FL), respectively, and selective reabsorption of a part of their FL band. Crystals 1 and 2 exhibit optical-path-dependent low loss emissions at the termini of crystal in their straight and even in extremely bent geometries. Interestingly, the excitation position-dependent optical modes appear in both linear and bent waveguides of crystals 1 and 2, confirming their light-trapping ability.
KW - Crystal growth
KW - Fluorescence
KW - Mechanophotonics
KW - Micromanipulation
KW - Optical waveguides
PY - 2022
DO - https://doi.org/10.1002/chem.202200905
SN - 0947-6539
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-55018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Müller, Anja
T1 - Determination of the actual morphology of core-shell nanoparticles by advanced X-ray analytical techniques: A necessity for targeted and safe nanotechnology
N2 - Even though we often do not knowingly recognize them, nanoparticles are present these days in most areas of our daily life, including food and its packaging, medicine, pharmaceuticals, cosmetics, pigments as well as electronic products, such as computer screens. The majority of these particles exhibits a core-shell morphology either intendedly or unintendedly. For the purpose of practicability, this core-shell nanoparticle (CSNP) morphology is often assumed to be ideal, namely a spherical core fully encapsulated by a shell of homogeneous thickness with a sharp interface between core and shell material. It is furthermore widely presumed that all nanoparticles in the sample possess the same shell thickness. As a matter of fact, most real CSNPs deviate in several ways from this ideal model with quite often severe impact on how efficiently they perform in a specific application.
The topic of this cumulative PhD thesis is the accurate characterization of the actual morphology of CSNPs by advanced X-ray analytical techniques, namely X-ray photoelectron spectroscopy (XPS) and scanning transmission X-ray microscopy (STXM). A special focus is on CSNPs which deviate from an ideal core-shell morphology. In the paper from 2019 nanoparticle shell thicknesses are extracted from the elastic-peak intensities in an XPS spectrum based on an ideal particle morphology. This happens for a series of CSNP samples comprising a poly(tetrafluoroethylene) (PTFE) core and either a poly(methyl methacrylate) (PMMA) or polystyrene (PS) shell. The same paper as well as the paper from 2020 demonstrate for the first time, that the analysis of the inelastic background in an XPS spectrum of CSNPs can identify and quantify the heterogeneity of the shell and the incomplete encapsulation of the core.
The result from an XPS experiment is always an average across a large nanoparticle ensemble. Deviations from an ideal morphology within a single particle of the sample cannot be assessed separately. As opposed to that, a spatial resolution of 35 nm enables STXM to visualize the interior of single CSNPs which exhibit a sufficient X-ray absorption contrast between core and shell material. In the paper from 2018 a STXM analysis is demonstrated based on the example of the PTFE-PS CSNP samples already mentioned in the previous paragraph.
In the publication from 2021 (Ca/Sr)F₂ core-shell like nanoparticle ensembles for the practical use in, among others, antireflective coatings are investigated. These nanoparticles do not possess a sharp interface between core and shell material, which is why a shell thickness determination as described in the second paragraph is inappropriate. Instead, in-depth profiles of the chemical composition are obtained by XPS experiments based on synchrotron radiation with variable X-ray photon energy to elucidate the internal morphology of the particles. Additionally, theoretical in-depth profiles of Ca and Sr XPS peak intensities are simulated, in order to facilitate the interpretation of the experiments. Thus, an enrichment of CaF₂ at the particle surface was determined, which could hardly have been assessed by any other analytical technique. Because this kind of non-destructive depth profiling by XPS is very demanding, more than usual effort is spent on gapless documentation of the experiments to ensure full reproducibility.
Due to the vast diversity of nanoparticles differing in material, composition and shape, a measurement procedure cannot unalteredly be transferred from one sample to another. Nevertheless, because the papers in this thesis present a greater depth of reporting on the experiments than comparable publications, they constitute an important guidance for other scientists on how to obtain meaningful information about CSNPs from surface analysis.
N2 - Obwohl wir sie oft nicht bewusst wahrnehmen, sind Nanopartikel heutzutage in den meisten Bereichen unseres Alltags präsent, unter anderem in Lebensmitteln und ihren Verpackungen, Medizin, Medikamenten, Kosmetik, Pigmenten und in elektronischen Geräten wie Computermonitoren. Ein Großteil dieser Partikel weist, beabsichtigt oder unbeabsichtigt, eine Kern-Schale Morphologie auf. Einfachheitshalber wird diese Morphologie eines Kern-Schale-Nanopartikels (CSNP) oft als ideal angenommen, d.h. als ein sphärischer Kern, der komplett von einer Schale homogener Dicke bedeckt ist, mit einer scharfen Grenzfläche zwischen Kern- und Schalenmaterial. Außerdem wird vielfach auch davon ausgegangen, alle Partikel der Probe hätten gleiche Schalendicken. Tatsächlich weichen die meisten realen CSNPs in verschiedenster Weise von diesem Idealmodell ab, mit oft drastischen Auswirkungen darauf, wie gut sie ihre Aufgabe in einer bestimmten Anwendung erfüllen.
Das Thema dieser kumulativen Doktorarbeit ist die exakte Charakterisierung der wirklichen Morphologie von CSNPs mit modernen Röntgen-basierten Methoden, konkret Röntgen-Photoelektronen-Spektroskopie (XPS) und Raster-Transmissions-Röntgen-Mikroskopie (STXM). Der Fokus liegt insbesondere auf CSNPs, die von einer idealen Kern-Schale-Morphologie abweichen. Im Artikel von 2019 werden Schalendicken von Nanopartikeln aus den elastischen Peakintensitäten im XPS-Spektrum unter Annahme einer idealen Partikelmorphologie abgeleitet. Dies geschieht für eine Reihe von CSNP-Proben, welche aus einem Polytetrafluoroethylen- (PTFE) Kern und entweder einer Polymethylmethacrylat- (PMMA) oder Polystyrol- (PS) Schale bestehen. Sowohl dieser Artikel als auch der von 2020 zeigen erstmals, dass die Auswertung des inelastischen Untergrunds eines CSNP-XPS-Spektrums in der Lage ist, die Heterogenität der Schale und die unvollständige Ummantelung des Kerns zu identifizieren und zu quantifizieren.
Das Ergebnis eines XPS-Experiments ist immer ein Mittelwert über ein großes Nanopartikelensemble. Inwiefern ein einzelner Partikel innerhalb der Probe von einer idealen Morphologie abweicht, kann nicht gesondert erfasst werden. Im Gegensatz dazu kann STXM mit einer räumlichen Auflösung von 35 nm das Innere einzelner CSNPs visualisieren, sofern sie genügend Röntgenabsorptionskontrast zwischen Kern- und Schalenmaterial aufweisen. Im Artikel von 2018 wird am Beispiel der bereits im vorherigen Abschnitt genannt PTFE-PS-CSNPProben eine solche STXM-Untersuchung demonstriert.
In der Veröffentlichung von 2021 werden Kern-Schale-artige (Ca/Sr)F₂-Nanopartikel für den praktischen Einsatz in unter anderem entspiegelnden Beschichtungen untersucht. Da hier keine scharfe Grenzfläche zwischen Kern- und Schalenmaterial vorliegt, ist eine Schalendickenbestimmung, wie sie im zweiten Abschnitt diskutiert wird, nicht sinnvoll. Stattdessen werden mit Hilfe von XPS, angeregt mit Synchrotronstrahlung bei variabler Röntgenphotonenenergie, Tiefenprofile der chemischen Zusammensetzung generiert, um die innere Morphologie der Partikel aufzuklären. Zusätzlich werden theoretische Tiefenprofile der Ca- und Sr-XPS-Peakintensitäten simuliert, um die Interpretation der Experimente zu erleichtern. So wurde eine CaF₂-Anreicherung an der Oberfläche der Partikel festgestellt, die kaum mit einer anderen analytischen Methode hätte entdeckt werden können. Da diese zerstörungsfreie Bestimmung von XPS-Tiefenprofilen sehr anspruchsvoll ist, wird noch mehr als üblich auf die lückenlose Dokumentation des Experiments geachtet, um vollständige Reproduzierbarkeit zu gewährleisten.
Aufgrund der enormen Vielfalt an CSNPs, die sich in Material, Zusammensetzung und Form unterscheiden, kann eine Messmethode nicht völlig unverändert von einer Probe auf eine andere übertragen werden. Nichtsdestotrotz, da die als Teil dieser Doktorarbeit präsentierten Artikel eine deutlich ausführlichere Beschreibung der Experimente enthalten als vergleichbare Publikationen, stellen sie eine wichtige Anleitung für andere Wissenschaftler dafür dar, wie aussagekräftige Informationen über CSNPs durch Oberflächenanalytik erhalten werden können.
KW - Core-shell nanoparticle (CSNP)
KW - X-ray photoelectron spectroscopy (XPS)
KW - Scanning transmission X-ray microscopy (STXM)
PY - 2022
DO - https://doi.org/10.18452/24312
SP - i
EP - 243
PB - Humboldt-Universität
CY - Berlin
AN - OPUS4-54991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Ultrakurzpulslaser induzierte Oxidschichten zur Reduktion von Reibung und Verschleiß auf Metalloberflächen
N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nano- und Mikrostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet.
T2 - Workshop "Nachhaltigkeit durch Tribologische Schichten" - Europäische Forschungsgesellschaft Dünne Schichten e.V.
CY - Karlsruhe, Germany
DA - 17.05.2022
KW - Laser-induzierte periodische Oberflächenstrukturen
KW - Reibungsreduktion
KW - Verschleißreduktion
KW - Oberflächenmodifikation
KW - Oxidation
KW - Additive
PY - 2022
AN - OPUS4-54849
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spaltmann, Dirk
T1 - Tribological performance of FS-laser-induced periodic surface structures on titanium alloy against different counter-body materials using a ZDDP lubricant additive
N2 - In this study the so-called laser-induced periodic surface structures (LIPSS, ripples) were produced on titanium alloy (Ti6Al4V) surfaces upon scan processing in air by a Ti:sapphire femtosecond (fs) laser. The tribological performance of the resulting surfaces was qualified in linear reciprocating sliding tribological tests (RSTT) against balls made of different materials (100Cr6 steel/Al2O3/Si3N4) using different oil-based lubricants. The admixture of the additive 2-ethylhexylzinc-dithiophosphate (ZDDP) to a base oil containing only anti-oxidants and temperature stabilizers disclosed the synergy of the additive with the laser-oxidized nanostructures. This interplay between the laser-textured sample topography and the local chemistry in the tribological contact area reduces friction and wear.
T2 - 7th World Tribology Congress - WTC 2022
CY - Lyon, France
DA - 11.07.2022
KW - Lubricant additives
KW - Laser-induced periodic surface structures (LIPSS)
KW - Wear
KW - Friction
PY - 2022
AN - OPUS4-55318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Smart Machines, New Materials, Automated Future
N2 - In pursuing the automated synthesis of metal nanoparticles (NPs), the capabilities of the “Chemputer” are deployed, for the first time, into the field of inorganic chemistry. Metal NPs have a substantial impact across different fields of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver NPs are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize Ag NPs often do not result in well-defined products, the main obstacles being high polydispersity or a lack of particle size tunability.
The Chemputer is a modular, automated platform developed by the Cronin group for execution of multi-step, solution based organic synthesis. The machine has been further implemented at BAM, where we used this setup to perform automated organic syntheses, autonomously controlled by feedback derived from online NMR. In the Chemputer liquids can be transferred across a backbone, constructed from HPLC selection valves and syringe pumps. The Chemputer operates in a batch mode, common laboratory devices, such as heaters and glassware like round bottom flasks, are connected to the backbone, forming reaction modules. Solutions can be manipulated in these modules, and as all operations are controlled through a software script, reproducibility among individual syntheses is high. Likewise, any adjustments of the synthesis conditions, if required, are straightforward to implement and are documented in the reaction log file and a code versioning system.
We characterised Chemputer-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties. The approach is an important first step towards the automation of nanoparticle syntheses in a modular, multipurpose platform. The modularity of the Chemputer opens many possibilities for the synthesis of a variety of different NP morphologies and sizes and potentially more complex structures. These advances and further work can help in the general investigations of silver nanoparticles by supplying a reliable and reproducible method of their synthesis and removing tacit knowledge by significantly reducing the experimental bias.
T2 - Analytica 2022
CY - Munich, Germany
DA - 21.06.2022
KW - Automated synthesis
KW - Nanoparticles
PY - 2022
AN - OPUS4-55198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Trash to treasure: recovery of transition metal phosphates for (electro-)catalytical applications
N2 - Wastewaters containing high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants. At the same time phosphorous and transition metals constitute valuable resources. Here, we report the synthesis routes for Co- and Ni-struvites (NH4MPO4∙6H2O, M = Ni2+, Co2+) out of aqueous solutions resembling synthetic/industrial waste water compositions, and allowing for P, ammonia and metal co-precipitation. Furthermore, the as-obtained struvites were further up-cycled. When heated, these transition metal phosphates (TMPs) demonstrate significant changes in the degree of crystallinity/coordination environment involving a high amount of amorphous phases and importantly develop mesoporosity (Figure 1). In this regard, amorphous and mesoporous TMPs are known to be highly promising (electro-)catalysts.
Amorphous phases do not represent a simple “disordered” crystal but more a complex system with a broad range of compositions and physicochemical properties, which remain mostly unknown. Consequently, we investigated the recrystallization and amorphization process during thermal treatment and a resolved the complex amorphous/crystalline structures (Figure 2). As a proof-of-principle for their applicational use, the as-obtained TMPs demonstrate significant proton conductivity properties similar to apatite-like structures from room to high temperatures (>800°C).
Hence, we have developed a promising recycling route in which environmental harmful contaminants like PO43-, NH4+ and 3d metals would be extracted out of waste waters in the form of precursor raw materials. These raw materials can be then further up-cycled through a simple thermal treatment for their specific application in electrocatalysis.
T2 - Goldschmidt Conference 2022
CY - Hawai'i, USA
DA - 10.07.2022
KW - Mesoporosity
KW - Amorphous phases
KW - Transition metals
KW - Struvite
KW - Phosphates
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552852
UR - https://conf.goldschmidt.info/goldschmidt/2022/meetingapp.cgi/Paper/9501
AN - OPUS4-55285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohamed, W. A. A.
A1 - Fahmy, Alaa
A1 - Helal, A.
A1 - Ahmed, E. A. E.
A1 - Elsayed, B. A.
A1 - Kamoun, E. A.
A1 - Gad, E. A. M.
T1 - Degradation of local Brilliant Blue R dye in presence of polyvinylidene fluoride/MWCNs/TiO2 as photocatalysts and plasma discharge
N2 - The need of clean water and the water-poor are increasing daily in the world. In addition, we are facing a dramatic increase in the industrial pollutions of rivers and groundwater, which led us to find a new way to treat industrial pollutants. The plasma discharge technique is one of the important, safe, and applicable for industrial wastewater decontamination. Decolorization of Brilliant Blue R (BBR) dye as a hazard material was noticed when the contaminated solution was exposed to the plasma discharge technique. The combination between the nonthermal plasma and catalysts was evaluated in this work to optimize the degradation efficiency. The PVDF/(MWCNTs/TiO2) as three system composites was employed to enhance the nonthermal plasma performance. The surface area, phase purity, shape, and photonic efficiency were characterized employing XRD, FTIR, SEM, DSC, and UV–Vis. techniques. The obtained results of degradation using NTP technique in presence of the PVDF/MWCNTs catalyst have been enhanced the BBR dye degradation by 19% than only plasma treatment for 20 min.
The durability processes of prepared PVDF/(MWCNTs/TiO2) was investigated and evaluated until 8 solar photocatalytic process repeating times.
KW - Brilliant Blue R
KW - MWCNT
KW - PVDF
PY - 2022
DO - https://doi.org/10.1016/j.jece.2021.106854
VL - 10
IS - 1
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-54386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macková, A.
A1 - Malinský, P.
A1 - Jagerová, A.
A1 - Mikšová, A.
A1 - Lalik, O.
A1 - Nekvindová, P.
A1 - Mistrík, J.
A1 - Marvan, P.
A1 - Sofer, Z.
A1 - Holý, V.
A1 - Schütter, Jan David
A1 - Kentsch, U.
A1 - Azarov, A.
A1 - Galeckas, A.
T1 - Energetic Au ion beam implantation of ZnO nanopillars for optical response modulation
N2 - Nanopillars of ZnO were implanted with Au-400 keV ions at various ion fluences from 1 × 1015 cm−2 to 1 × 1016 cm−2 and subsequently annealed at 750 °C for 15 min in order to reduce the implantation damage and to support Au nanoparticle (NP) aggregation. It was found that implantation-induced effects and thermal effects influence the Au NP coalescence as well as the quality of the ZnO nanopillars. Rutherford Back-Scattering spectrometry (RBS) showed the broader Au-depth profiles than it was theoretically predicted, but the Au-concentration maximum agrees well with prediction taking into account the effective ZnO layer density. The implantation at the higher fluences induced the morphology modification of the nanopillar layer evidenced by RBS and scanning electron microscopy (SEM). An indirect evidence of this effect was given by optical ellipsometry due to gradual refractive index changes in the ZnO nanopillars with the increased Au-ion fluence. Optical characterization of the Au-implanted and annealed nanopillars performed by means of photoluminescence (PL) and diffuse-reflectance spectroscopy (DRS) evidenced the surface plasmon resonance (SPR) activity of the embedded Au NPs. The SPR-enhanced scattering and PL emission observed in the spectral range 500–650 nm are ascribed to Au NPs or more complex Au-clusters. In addition, the ellipsometry measurements of extinction coefficient are found to corroborate well results from DRS, both indicating increase of SPR effect with the increase of Au-ion fluence and after the post-annealing.
KW - ZnO nanopillars
KW - Ion beam implantation
PY - 2022
DO - https://doi.org/10.1088/1361-6463/ac5486
VL - 55
IS - 21
SP - 1
EP - 14
PB - IOP Publishing
AN - OPUS4-54394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Martins, Ines
T1 - Carbamazepine Dihydroxybenzoic Acid Cocrystals: Exploring Packing Interactions and Reaction Kinetics
N2 - Herein, we present the mechanochemical formation of three new cocrystals containing the active pharmaceutical ingredient carbamazepine and dihydroxybenzoic acids as coformers (CBZ:2,4-DHBA 1:1, CBZ:2,5-DHBA 1:1, and CBZ:2,6-DHBA 1:1). Rietveld methods were used for three different purposes: (i) refining all structures solved using powder X-ray diffraction, (ii) performing a quantitative phase analysis of the diffraction data collected from ex situ mechanochemical reactions at different milling times, and (iii) determining the cocrystallization kinetic profiles. The rate of cocrystallization was found to be higher for the formation of CBZ:2,4-DHBA and CBZ:2,6-DHBA, reaching an equilibrium after 600 s of milling. In the case of CBZ:2,5-DHBA a short induction period of 20 s was detected prior to the start of the reaction and an equilibrium was reached after 1200 s. An empirical trend between the rate of cocrystallization and the structural complexity of the cocrystal product was found. The slowest cocrystallization rate observed for CBZ:2,5-DHBA corresponds to the crystal structure deviating substantially from the hydrogen-bonding motif found in the reactants.
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Kinetics
PY - 2021
DO - https://doi.org/10.1021/acs.cgd.1c00902
VL - 21
IS - 12
SP - 6961
EP - 6970
PB - ACS Publications
AN - OPUS4-54407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Ca-MOFs with varying fluorination degree
N2 - In current Li-ion batteries electrode materials consist typically of inorganic materials, such as LiCoO2, LiNixCoyMn1-zO2, LiFePO4, Li4Ti5O12. These materials struggle with toxicity or limited mineral resources, making them expensive. Therefore, eco-friendly, sustainable, and low-cost alternatives are researched for in recent years. A series of organic compounds were investigated as electrode materials for alkali-ion batteries. Among them organic carbonyl-based materials show reversible storage of lithium- or sodium-ions. Metal terephthalates stand out with their easy synthesis, moderate operational voltage and enhanced dissolution stability compared to other organic compounds. One degradation pathway consists of the dissolution of the electrode material by HF, formed in a side reaction by water and the fluorous electrolyte. Fluorinated metal terephthalates could offer higher dissolution stability against HF and less contamination by water due to their increased hydrophobicity.
The goal of this project is the synthesis and the investigation of the formation mechanism of a series of calcium-based MOFs with increasing fluorine content. For this purpose, we aimed for the construction of calcium-based MOFs with terephthalic acid (H2-pBDC), 2-fluoro-terephthalic acid (H2-2F-pBDC), 2,3,4,5-tetrafluoroterephthalic acid (H2-pBDC-F4), isophthalic acid (H2-mBDC) and 5-fluoro-isophthalic acid (H2-5F-mBDC).
T2 - SFB 1349 Wintersymposium 2022
CY - Berlin, Germany
DA - 15.03.2022
KW - Mechanochemistry
KW - Electrode materials
KW - Fluorinated MOFs
KW - In situ PXRD
PY - 2022
AN - OPUS4-54478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-Induced Periodic Surface Structures: when Maxwell meets Marangoni
N2 - Laser-Induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any material upon irradiation of solids with intense laser radiation. Nowadays, processing rates of up to m^2/min are enabling new industrial applications in medicine, optics, tribology, biology, etc. Depending on the specific type of LIPSS, their structural sizes typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, however, a controversial and vivid debate has emerged during the last two decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter reorganization processes, i.e. distinctly after the laser irradiation. This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
T2 - 16th International Conference on Laser Ablation (COLA 2021/22)
CY - Matsue, Japan
DA - 24.04.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser ablation
KW - Theoretical modelling
KW - Electromagnetic scattering
KW - Hydrodynamics
PY - 2022
AN - OPUS4-54716
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Morrison, C.
T1 - From lattice vibrations to molecular dissociation
N2 - The ease with which an energetic material can be initiated by mechanical impact is a critical parameter directing material safety and application. While impact sensitivity metrics are traditionally derived experimentally, recent developments have highlighted that the phenomenon is amenable to first principles simulation. In this chapter, we will outline a fully ab initio approach to predict the relative impact sensitivities of energetic materials based on the mechanochemical principles that link the impact event to vibrational energy transfer.
This mechanism is key to rationalizing how a mechanical impact—which deposits energy into the low-frequency lattice vibrations—results in a molecular response. By simulating the vibrational energy levels (the so-called phonon density of states, PDOS) using first-principles computational methods (typically dispersion-corrected plane-wave density functional theory, PW-DFT) we can calculate the relative rate of energy propagation from the delocalized low-energy lattice vibrations through to the localized molecular modes. The latter traps the energy, which eventually results in bond rupture through heightened vibrational excitation.
This method, based on vibrational up-pumping, offers a route toward predicting the impact sensitivities of a broad range of energetic materials, provided the crystal structure of the compound (or salt or co-crystal) is known. While it does not offer insight into the sensitizing roles undoubtedly played by crystal defects or grain boundaries, it does provide a level of understanding at the molecular and crystal packing levels. Correspondingly, this approach offers a feedback mechanism to chemists and materials scientists to guide the design of new materials with desired impact sensitivity behavior.
KW - Energetic materials
KW - Density functional theory
KW - Material design
PY - 2022
DO - https://doi.org/10.1016/B978-0-12-822971-2.00010-3
VL - 22
SP - 215
EP - 232
PB - Elsevier B.V.
AN - OPUS4-54717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n = 5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations probing the molecular mobility, a c-relaxation due to localized fluctuations as well as two glassy dynamics, the acore- and aalkyl-relaxation, were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n = 8 from a rigid constrained (n = 5,6) to a softer system (n = 10,12) was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene-like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition.
KW - Discotic liquid crystals
KW - Broadband dielectric spectroscopy
KW - Advanced calorimetry
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119212
VL - 358
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-54721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Side Chain length dependent dynamics and conductivity of Ionic Liquid crystals
N2 - We investigate the molecular dynamics and electrical conductivity for a homologous series of linear shaped guanidinium based cyclic ILCs that vary in alkyl chain length, CLCRs (R = 8, 10, 12, 14, 16) by employing broadband dielectric spectroscopy (BDS), and calorimetry comprised of Fast Scanning Calorimetry (FSC) and temperature modulated FSC (TMFSC). Besides conductivity at high temperatures, the dielectric dispersion reveals two relaxation modes: the fast γ and the slow α1 relaxation. The former is assigned to the localized fluctuations while the latter is due to segmental dynamics of the alkyl chains. The γ mode slows down for long chain length CLCs (12,14,16) compared to their shorter analogues. Calorimetric investigation reveals one process, the α2 process, for all ILCs. The α2 process for CLC10, 12, and 14 has a similar temperature dependence as the dielectric α1 relaxation, while for the CLC8 and 10, it's shifted to a higher temperature. For all CLCRs, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. This increase is due to the change in the underlying conduction mechanism from delocalized electron hopping in the crystalline phase to one-dimensional ion mobility in the columnar phase. The glassy dynamics shifts to higher temperatures with increasing alkyl chain length. Conversely, the DC conductivity drops by 3 orders of magnitude from CLC8 to CLC16.
T2 - APS March Meeting 2022
CY - Chicago, IL, USA
DA - 13.03.2022
KW - Glass transition
KW - Conductivity
KW - Fast Scanning Calorimetry
KW - Dynamics
PY - 2022
AN - OPUS4-54760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frunza, L.
A1 - Zgura, I
A1 - Ganea, C. P.
A1 - Schönhals, Andreas
T1 - Molecular dynamics of alkyl benzoate liquid crystals in the bulk state and in the surface layer of their composites with oxide nanopowders
N2 - This paper presents the results concerning monotropic nematic liquid crystals 4-pentylphenyl 40-alkyl benzoate (5PnB) (n = 3 or 5 carbon atoms in the alkyl chain). Their mesophase properties were supported by images of the polarized optical microscopy. Molecular dynamics in the bulk samples or in the composites prepared with aerosil A380 was investigated by broadband dielectric spectroscopy in a large temperature range, appropriately chosen. Thermo gravimetric and infrared investigations were additionally performed. The data were compared with those of structurally related nematics like cyanophenyl pentyl benzoates, which have a cyan group instead of the pentyl chain. The dielectric spectra of the bulk 3P5B and 5P5B demonstrate a dielectric behavior with several relaxation processes as expected for nematic liquid crystals. The temperature dependence of the relaxation rates (and of the dielectric strength) seems to have two distinguished regimes. Thus, in the isotropic state, at higher temperatures the data obey the Vogel–Fulcher–Tammann law, whereas an Arrhenius law is fitted at lower temperature, in a close similarity to the behavior of a constrained dynamic glass transition. Samples with a high density of silica (larger than 7 g aerosil/1 g of 5PnB) were prepared to observe a thin layer adsorbed on the particle surface; it was estimated that almost each guest 5PnB molecule interacts with the aerosil surface. For the composites only one main relaxation process is observed at frequencies much lower than those for the corresponding bulk, which was assigned to the dynamics of the molecules in the surface layer. Infrared spectroscopy shows that these molecules interact with the surface by the ester carbonyl group leading to the monolayer self-assembly at liquid–solid interface. We note once more the importance of the functional unit(s) for the interaction with the hydroxyl groups on the aerosil surface.
KW - Liquid crystals
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119374
SN - 0167-7322
VL - 359
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-54867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 3rd CEFMC meeting
CY - Kashmir, India
DA - 31.08.2022
KW - Mechanochemistry
KW - Crystal Engeneering
PY - 2022
AN - OPUS4-55641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy, advanced calorimetry and Neutron Scattering
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n=5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations probing the molecular mobility, a γ-relaxation due to localized fluctuations as well as two glassy dynamics the αcore and αalkyl relaxation were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n=8 from a rigid constrained (n=5,6) to a softer system (n=10,12) on a molecular lenght scale was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition.
T2 - 11th Conferenz on Broadband Dielectric Spectroscopy and its Applications
CY - San Sebastian, Spain
DA - 04.09.2022
KW - Discotic Liquid Crystals
PY - 2022
AN - OPUS4-55672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Inelastic and Quasielastic Neutron Scattering Experiments on Mircroporous Membranes for Green Separation processes
N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. These polymers are characterized by a high permeability and reasonable permselectivity. The latter point is somehow surprising because for microporous systems a more Knudson-like diffusion is expected then a size dependent temperature activated sieving process. It was argued in the framework of a random gate model that molecular fluctuations on a time scale from ps to ns are responsible for the permselectivity.
Her a series of microporous polynorbornenes with bulky Si side groups and a rigid backbone are considered which have different microporosity characterized by BET surface area values.
First inelastic time-of-flight neutron scattering measurements were carried out to investigate the low frequency density of state (VDOS). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. It was found the maximum position of the Boson peak correlates with the BET surface area value.
For two selected comparable polynorbornenes elastic scans as well as QENS measurements by a combination of neutron time-of-flight and backscattering are carried out. A low temperature relaxation process was found for both polymers. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized.
T2 - MLZ Conference 2022: Neutrons for mobility
CY - Lengries, Germany
DA - 31.05.2022
KW - Polymers of intrinsic Microporosity
PY - 2022
AN - OPUS4-55674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Pauw, Brian Richard
A1 - Marguet, S.
A1 - Skroblin, D.
A1 - Taché, O.
A1 - Krumrey, M.
A1 - Gollwitzer, C.
T1 - Small-angle X-ray scattering: characterization of cubic Au nanoparticles using Debye’s scattering formula
N2 - A versatile software package in the form of a Python extension, named CDEF (computing Debye’s scattering formula for extraordinary form factors), is proposed to calculate approximate scattering profiles of arbitrarily shaped nanoparticles for small-angle X-ray scattering (SAXS). CDEF generates a quasi-randomly distributed point cloud in the desired particle shape and then applies the open-source software DEBYER for efficient evaluation of Debye’s scattering formula to calculate the SAXS pattern (https://github.com/j-from-b/CDEF). If self-correlation of the scattering signal is not omitted, the quasi-random distribution provides faster convergence compared with a true-random distribution of the scatterers, especially at higher momentum transfer. The usage of the software is demonstrated for the evaluation of scattering data of Au nanocubes with rounded edges, which were measured at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II in Berlin. The implementation is fast enough to run on a single desktop computer and perform model fits within minutes. The accuracy of the method was analyzed by comparison with analytically known form factors and verified with another implementation, the SPONGE, based on a similar principle with fewer approximations. Additionally, the SPONGE coupled to McSAS3 allows one to retrieve information on the uncertainty of the size distribution using a Monte Carlo uncertainty estimation algorithm.
KW - X-ray scattering
KW - SAXS
KW - Non-spherical nanoparticles
KW - Nanoparticles
KW - Nanomaterials
KW - Debye scattering equation
KW - Simulation
KW - Data fitting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557652
DO - https://doi.org/10.1107/S160057672200499X
VL - 55
IS - Pt 4
SP - 993
EP - 1001
PB - International Union of Crystallography
CY - Chester, England
AN - OPUS4-55765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emamverdi, Farnaz
T1 - Molecular Mobility and Physical Aging of Polymers with Intrinsic Microporosity (PIM-1) Revisited: A Big Glassy World
N2 - Polymeric membranes represent a cost- and energy-efficient solution for gas separation. Recently Polymers of Intrinsic Microporosity (PIMs) have been in a great interest because of their outstanding BET surface area larger than 700m2/g and pore size smaller than 1 nm. PIMs are a promising candidate in gas separation with high permeability and appealing selectivity due to their inefficient packing derived from a combination of ladder-like rigid segments with sites of contortion. However, it is recognized this class of polymers suffer from decrease in performance with time due to physical aging. The initial microporous structures approach a denser state via local chain rearrangements, leading to a dramatic reduction in permeability. As chain packing during film casting and physical aging are the key factors determine the performance in separation applications, characterization of the molecular mobility in these materials has been proved to provide valuable information. In recent research on PIM-1 the archetypal PIM, a molecular relaxation process with high activation energy together with a significant conductivity in the glassy state has been found and explained with the formation of local intermolecular agglomerates due to interaction of π-electrons in aromatic moieties of the polymer backbone. In this work, the dielectric behavior of the polymeric films and their response upon heating (aging) were measured by isothermal frequency scans during different heating/cooling cycles in a broad temperature range down to 133K for the first time. Multiple dielectric processes following Arrhenius behavior were observed. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxations were discussed correlating to structural-properties of PIM-1. Up to now, no other work has studied the role of porosity and thermal history of PIM-1 film in dielectric processes. The goal is by eliminating thermal history and considering storing conditions provide better understanding on aging and plasticizing in high free volume glassy polymer PIM-1.
T2 - Euromembrane conference
CY - Copenhagen, Denmark
DA - 29.11.2021
KW - Physical aging
KW - Membrane
KW - Microporous structure
KW - Glassy polymer
PY - 2021
AN - OPUS4-55758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced Periodic Surface Structures (LIPSS): Mechanisms, Applications, and unsolved Problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m^2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches. Moreover, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry
T2 - 10th International LIPSS Workshop 2022
CY - Orléans, France
DA - 21.09.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Femtosecond laser processing
KW - Time-resolved coherent scattering
PY - 2022
AN - OPUS4-55814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Das, Chayanika
A1 - Emmerling, Franziska
T1 - Mechanochemical Synthesis of Phosphonate-Based Proton Conducting Metal-Organic Frameworks
N2 - Water-stable metal−organic frameworks (MOFs) with proton-conducting behavior have attracted great attention as promising materials for proton-exchange membrane fuel cells. Herein, we report the mechanochemical gram-scale synthesis of three new mixed-ligand phosphonate-based MOFs, {Co(H2PhDPA)(4,4′-bipy)H2O)·2H2O}n (BAM-1), {Fe(H2PhDPA)(4,4′-bipy) (H2O)·2H2O}n (BAM-2), and {Cu(H2PhDPA)(dpe)2(H2O)2·2H2O}n (BAM-3) [where H2PhDPA = phenylene diphosphonate, 4,4′-bipy = 4,4′-bipyridine, and dpe = 1,2-di(4-pyridyl)ethylene]. Single-crystal X-ray diffraction measurements revealed that BAM-1 and BAM-2 are isostructural and possess a three-dimensional (3D) network structure comprising one-dimensional (1D) channels filled with guest water molecules. Instead, BAM-3 displays a 1D network structure extended into a 3D supramolecular structure through hydrogenbonding and π−π interactions. In all three structures, guest water molecules are interconnected with the uncoordinated acidic hydroxyl groups of the phosphonate moieties and coordinated water molecules by means of extended hydrogen-bonding interactions. BAM-1 and BAM-2 showed a gradual increase in proton conductivity with increasing temperature and reached 4.9 × 10−5 and 4.4 × 10−5 S cm−1 at 90 °C and 98% relative humidity (RH). The highest proton conductivity recorded for BAM-3 was 1.4 × 10−5 S cm−1 at 50 °C and 98% RH. Upon further heating, BAM-3 undergoes dehydration followed by a phase transition to another crystalline form which largely affects its performance. All compounds exhibited a proton hopping (Grotthuss model) mechanism, as suggested by their low activation energy.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Proton conductivity
PY - 2022
DO - https://doi.org/10.1021/acs.inorgchem.2c01023
VL - 61
SP - 10801
EP - 10809
PB - ACS Publications
AN - OPUS4-55448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghazanfari, M. R.
A1 - Vittadello, L.
A1 - Al-Sabbagh, Dominik
A1 - Santhosh, A.
A1 - Frankcom, C.
A1 - Fuß, F.
A1 - von Randow, C. A.
A1 - Siemensmeyer, K.
A1 - Vrijmoed, J. C.
A1 - Emmerling, Franziska
A1 - Jerabek, P.
A1 - Irmlau, M.
A1 - Thiele, G.
T1 - Remarkable Infrared Nonlinear Optical, Dielectric, and Strong Diamagnetic Characteristics of Semiconducting K3[BiS3]
N2 - The ternary sulfido bismuthate K3[BiS3] is synthesized in quantitative yields. The material exhibits nonlinear optical properties with strong second harmonic generation properties at arbitrary wavelengths in the infrared spectral range and a notable laser-induced damage threshold of 5.22 GW cm−2 for pulsed laser radiation at a wavelength of 1040 nm, a pulse duration of 180 fs, and a repetition rate of 12.5 kHz. K3[BiS3] indicates semiconductivity with a direct optical band gap of 2.51 eV. Dielectric and impedance characterizations demonstrate κ values in the range of 6−13 at 1 kHz and a high electrical resistivity. A strong diamagnetic behavior with a susceptibility of −2.73 × 10−4 m3 kg−1 at room temperature is observed. These results suggest it is a promising nonlinear optical candidate for the infrared
region. The synergic physical characteristics of K3[BiS3] provide insight into the correlation of optical, electrical, and magnetic properties.
KW - Electrical properties
KW - Insulators
KW - Materials
KW - Nonlinear optics
KW - Quantum mechanics
PY - 2022
DO - https://doi.org/10.1021/acs.jpclett.2c01689
VL - 13
IS - 30
SP - 6987
EP - 6993
PB - ACS Publications
AN - OPUS4-55456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystal systems: Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (poly-morphic) cocrystals, metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results.
Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 25th International Conference on the Chemistry of the Organic Solid State (ICCOSS XXV)
CY - Ohrid, Macedonia
DA - 03.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Crystal Engineering
PY - 2022
AN - OPUS4-55413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystals systems
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (polymorphic) cocrystals, metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 5ECQUL Forging Bonds
CY - Lisbon, Portugal
DA - 12.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - N-Chlorination
PY - 2022
AN - OPUS4-55414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Shaken not stirred: enhancing the flavor of mechanochemistry
N2 - compounds and cocrystals. The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. Time-resolved in situ investigations of milling reactions (Figure 1) provide direct insights into the underlying mechanisms. We recently introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD and XAS combined with Raman spectroscopy and thermography. The presented setup allows the detection of crystalline, amorphous, eutectic, and liquid intermediates. Furthermore, the chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key to future optimization of mechanochemical syntheses. In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals and coordination polymers. Our results indicate that time-resolved in situ investigations of mechanochemical processes are key for tuning and optimizing mechanochemical syntheses allowing to unleash the potential of mechanochemistry for a green materials design.
T2 - 2nd National Crystallographic Meeting Lisbon, Portugal
CY - Lisbon, Portugal
DA - 15.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Crystal
PY - 2022
AN - OPUS4-55415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystal systems: Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.1 Here we will discuss our recent results investigating the formation of (polymorphic) cocrystals2–3 and metal-organic frameworks,4 thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved.6 Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 10th International conference on Mechanochemistry and Mechanical Alloying
CY - Cagliari, Italy
DA - 06.06.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Cocrystal
PY - 2022
AN - OPUS4-55421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehri, S.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Dyre, J.C.
A1 - Ingebrigtsen, T.S.
T1 - Lines of invariant physics in the isotropic phase of the discotic Gay-Berne model
N2 - The Gay-Berne model is studied numerically with a choice of parameters allowing for the formation of a discotic liquid crystal at low temperatures. We show that the model has strong virial potential-energy correlations in the isotropic phase at high temperatures, i.e., it obeys the criterion for the existence of isomorphs, which are curves of approximately invariant structure and dynamics. These properties are demonstrated to be approximately invariant in reduced units along the isomorph studied. The isomorph is described well by the constant density-scaling exponent 11.5, a number that is significantly larger than the density-scaling exponents of various Lennard-Jones models that are always below 6.
KW - Liquid Crystal
KW - Molecular Dynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547611
DO - https://doi.org/10.1016/j.nocx.2022.100085
VL - 14
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-54761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishmastnehi, Moslem
A1 - Stawski, Tomasz
T1 - Crystals of Gypsum in Hands of Masters
N2 - The microstructure of most Seljuk and Ilkhanid stucco decorations consists of micrometer-sized crystals of gypsum. The stucco-masters of these periods (neither nowadays stucco-masters) were not able to directly control the properties of these tiny crystals with their hands or centimeter-sized tools. There are, however, traces of chaîne opératoire accumulated in the materialistic body of these pieces, some of which could be explored through an interdisciplinary approach. Such an investigation requires very careful in situ observation of the macrostructure, and scientific analyses of the material to discover part of the production process for each body of stucco. Furthermore, there are deterioration factors, some of which are not yet fully understood, and should be identified using modern analytical instruments. These damaging factors could easily affect the micro and macro structure of a stucco decoration, influencing our interpretation. The concept of chaîne opératoire reframes our questions about the production process and probable dating technique of Seljuk and Ilkhanid stuccoes, while analyses of labmade replicas and historic materials enhance our understanding and interpretation of these materials. Here we present the results of such a study for a large body of Seljuk and Ilkhanid stucco decorations at various sites in Iran, and present the potential of this approach as a new perspective in this field of research.
T2 - Stucco in the Architecture of Iran and Neighbouring Lands
CY - Bamberg, Germany
DA - 04.05.2022
KW - Gypsum
KW - Stuccos
KW - Crystallization
PY - 2022
AN - OPUS4-54782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Stawski, Tomasz
ED - Van Driessche, A. E. S.
T1 - Special issue "Formation of sulfate minerals in natural and industrial environments"
N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods.
KW - Calcium sulfate
KW - Sulfates
PY - 2020
UR - https://www.mdpi.com/journal/minerals/special_issues/FSMNIE
SN - 2075-163X
VL - 10(9)-12(3)
SP - 10-812-1
EP - 12-299-3
PB - MDPI
CY - Basel
AN - OPUS4-54700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Van Driessche, A. E. S.
T1 - Editorial for special issue "Formation of sulfate minerals in natural and industrial environments"
N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods.
KW - Calcium sulfate
KW - Sulfates
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546794
DO - https://doi.org/10.3390/min12030299
SN - 2075-163X
VL - 12(3)
IS - Special issue "Formation of sulfate minerals in natural and industrial environments"
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-54679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - X-ray hazards and radiation protection aspects in ultrashort laser processing
N2 - Ultrashort pulse laser micromachining at repetition rates of several hundreds of kHz allows a cost-effective high precision manufacturing, which makes this method attractive for many industrial applications. Upon exceeding a critical laser intensity, hard X-ray radiation is generated as a side effect. Even if the emitted X-ray dose per laser pulse is low, for currently available high-repetition-rate laser systems the accumulated X-ray dose becomes significant and radiation safety must be considered. Influences of the processing parameters are discussed and radiation protection aspects will be outlined
T2 - AKL’22 – International Laser Technology Congress
CY - Aachen, Germany
DA - 04.05.2022
KW - Ultrashort pulse laser processing
KW - X-ray emission
KW - Radiation protection
PY - 2022
AN - OPUS4-54805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chambers, M. S.
A1 - Hunter, R. D.
A1 - Hollamby, M. J.
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Danks, A. E.
A1 - Schnepp, Z.
T1 - In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C
N2 - Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows:
Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles.
KW - Small-angle X-ray Scattering
KW - SAXS
KW - Diffraction
KW - XRD
KW - Scattering
KW - Sol-gel
KW - Iron nitride
KW - Nanoparticles
KW - Iron carbide
KW - Catalyst
KW - In-situ
KW - Ex-situ
KW - Synthesis
KW - Synchrotron
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548226
DO - https://doi.org/10.1021/acs.inorgchem.1c03442
VL - 61
IS - 18
SP - 6742
EP - 6749
PB - ACS Publications
CY - Washington
AN - OPUS4-54822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 8)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852823
PB - Zenodo
CY - Geneva
AN - OPUS4-57448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Automation of machine learning driven interatomic potential generation for predicting vibrational properties
N2 - Investigating the phononic properties is beneficial for predicting low thermal conductivity thermoelectric materials.1–3 Employing density functional theory4 takes many calculation steps and consumes a lot of computational resources.5,6 Using machine learning driven interatomic potentials (MLIP, e.g., Gaussian approximation potential,8 GAP) opens up a faster route to phonons7 but in most cases, the potentials are specifically tailored for a certain compound. In this work, we automate the generation of such MLIPs in a Python code-based workflow, based on the automation tools atomate29 and pymatgen10 which combines the automatic DFT computations with the automated fitting of GAPs. Automation enables easier testing, benchmarking and validation.11 We aim to provide the workflow-generated potentials for storage in databases.
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Thermoelectrics
PY - 2023
AN - OPUS4-57932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Quantum chemical bonding analysis of functional materials using LOBSTER and automated workflows
N2 - A talk on how to use LOBSTER and automated workflows (supported by LobsterPy, atomate2 and more) to do quantum chemical bonding analysis for (functional) materials design.
T2 - Gastvortrag Inorganic Chemistry Laboratory, University of Oxford
CY - Oxford, UK
DA - 04.05.2023
KW - Chemical bonding
KW - Automated workflows
KW - Functional materials
PY - 2023
AN - OPUS4-57933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Workflows and automation (lecture/tutorial)
N2 - A lecture and tutorial on how to use workflows and automation methods for quantum chemical calculations.
T2 - Invited lecture
CY - Oxford, UK
DA - 28.04.2023
KW - Workflows
KW - Automation
KW - Quantum chemical bonding analysis
PY - 2023
AN - OPUS4-57934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bustamante, Joana
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - George, Janine
T1 - Thermodynamic and Thermoelectric Properties of the Canfieldite, (Ag8SnS6 ), in the Quasi-Harmonic Approximation
N2 - Argyrodite-type materials have lately sparked a lot of research interest due to their thermoelectric properties.One promising candidate is canfieldite (Ag8SnS6), which has a Pna21 orthorhombic crystal structure at room temperature (RT). Recently, a new low-temperature (LT) phase transition of canfieldite at 120K has been found. Here, we investigate structural, vibrational and thermodynamic properties of Ag8SnS6 at room- and low-temperature employing density functional theory (DFT) and lattice dynamics computations. Thermal properties calculations were based on the quasi-harmonic approximation (QHA) as implemented in phonopy. We achieve good agreement with experiments. Thermal properties such as the constant-pressure heat capacity (Cp) and thermal conductivity are very close to experimental measurements. Furthermore, we compared RT and LT Ag8SnS6 Grüneisen parameters with argyrodites analogues, Ag8XS6 (X = Sn, Si, Ge), to arrive at an improved
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - Thermoelectric materials
KW - DFT
KW - QHA
KW - Grüneisen parameter
PY - 2023
AN - OPUS4-57887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 33th European Crrystallography Meeting
CY - Versailles, France
DA - 23.08.2022
KW - Mechanochemistry
KW - Cocrystals
KW - Kinetics
KW - Polymorphs
PY - 2022
AN - OPUS4-55586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Structure-mechanical property correlation of a series of 4-(1-Napthylvinyl) pyridine based cocrystals
N2 - We obtained three 4-(1-Napthylvinyl) pyridine based cocrystals ( 1–3 ) and studied its structure mechan- ical property correlation which aimed towards various applications for photo switches, mechanical ac- tuators etc. Selection of coformer molecules is important in fine tuning mechanical property outcome of synthesized cocrystals. Amongst three cocrystals, cocrystal 1 is mechanically flexible and its mechani- cal property is attributed to underlying crystal packing features which is in line with existing elastically bendable crystals while other two cocrystals ( 2, 3 ) are brittle in nature. Hirshfeld analysis was carried out to illustrate structure-property correlation particularly in terms of number as well as types of non- covalent interactions in the lattice and further to corroborate the space of the molecules in the lattice.
KW - Cocrystals
KW - Mechanical properties
KW - Halogen bond interaction
KW - Structure-mechanical property correlation
PY - 2022
DO - https://doi.org/10.1016/j.molstruc.2022.133670
SN - 0022-2860
VL - 1268
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thekkeppat, N. P.
A1 - Bhattacharya, Biswajit
A1 - Tothadi, S.
A1 - Ghosh, S.
T1 - Mechanically flexible crystals of styryl quinoline derivatives
N2 - Herein, we report three crystals of styryl quinoline derivatives. All these three crystals are mechanically flexible crystals, isostructural and also all of them comply with the common underlying features for elas- tic flexibility like absence of slip plane, criss-cross packing arrangement of neighbouring tapes, presence of weak and dispersive interactions such as halogen bonds, hydrogen bonds etc. The interactions facilitate easy movement of molecules under application of pressure thereby imparting elasticity. Further, the crys- tals were found to be blue light emitting making them promising candidates for optical waveguides. The optical properties were combined with flexibility by using crystal engineering approach towards achiev- ing various applications such as flexible OLEDs, optical waveguides, flexible optoelectronics etc.
KW - Mechanical flexibility
KW - Halogen bond
KW - Fluorescence
PY - 2022
DO - https://doi.org/10.1016/j.molstruc.2022.133293
SN - 0022-2860
VL - 1265
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grunwald, M. A.
A1 - Hagenlocher, S. E.
A1 - Turkanovic, L.
A1 - Bauch, S. M.
A1 - Wachsmann, S. B.
A1 - Altevogt, L. A.
A1 - Ebert, M.
A1 - Knöller, J. A.
A1 - Raab, A. R.
A1 - Schulz, F.
A1 - Kolmangadi, Mohamed A.
A1 - Zens, A.
A1 - Huber, P.
A1 - Schönhals, Andreas
A1 - Bilitiewski, U.
A1 - Laschat, S.
T1 - Does thermotropic liquid crystalline self-assembly control biological activity in amphiphilic amino acids? – tyrosine ILCs as a case study
N2 - Amphiphilic amino acids represent promising scaffolds for biologically active soft matter. In order to understand the bulk self-assembly of amphiphilic amino acids into thermotropic liquid crystalline phases and their biological properties a series of tyrosine ionic liquid crystals (ILCs) was synthesized, carrying a benzoate unit with 0–3 alkoxy chains at the tyrosine unit and a cationic guanidinium head group. Investigation of the mesomorphic properties by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (WAXS, SAXS) revealed smectic A bilayers (SmAd) for ILCs with 4-alkoxy- and 3,4-dialkoxybenzoates, whereas ILCs with 3,4,5-trisalkoxybenzoates showed hexagonal columnar mesophases (Colh ), while different counterions had only a minor influence. Dielectric measurements revealed a slightly higher dipole moment of non-mesomorphic tyrosine-benzoates as compared to their mesomorphic counterparts. The absence of lipophilic side chains on the benzoate unit was important for the biological activity. Thus, non-mesomorphic tyrosine benzoates and crown ether benzoates devoid of additional side chains at the benzoate unit displayed the highest cytotoxicities (against L929 mouse fibroblast cell line) and antimicrobial activity (against Escherichia coli DTolC and Staphylococcus aureus) and promising selectivity ratio in favour of antimicrobial activity.
KW - Liquid Crystals
PY - 2023
DO - https://doi.org/10.1039/d3cp00485f
SN - 1463-9076
VL - 25
IS - 26
SP - 17639
EP - 17656
PB - RCS
AN - OPUS4-57796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madeja, B.
A1 - Gebauer, D.
A1 - Marsiske, M. R.
A1 - Ott, A.
A1 - Rückel, M.
A1 - Rosenberg, R.
A1 - Baken, A.
A1 - Stawski, Tomasz M.
A1 - Fernandez-Martinez, A.
A1 - Van Driessche, A.E.S.
A1 - Cölfen, H.
A1 - Kellermeier, M.
T1 - New insights into the nucleation of portlandite and the effects of polymeric additives
N2 - The crystallization of calcium hydroxide (Ca(OH)2, CH, portlandite) is a key process during the early stages of cement hydration. In the present work, we have revisited the formation of this mineral through nucleation and growth from supersaturated aqueous solutions, in the light of the currently emerging picture of multistage “non-classical” crystallization. To that end, we developed a titration-based assay, in which stock solutions of both relevant ions are added simultaneously into a reservoir, where supersaturation increases slowly at constant stoichiometry until nucleation occurs. This procedure allows both pre- and early post-nucleation phenomena to be analyzed quantitatively. Complementarily, the early stages of portlandite mineralization were probed by various advanced characterization techniques, including cryo-transmission electron microscopy (cryo-TEM), in-situ small-angle X-ray scattering (SAXS), pair distribution function (PDF) analysis of high-energy X-ray scattering (HEXS) data, and analytical ultracentrifugation (AUC). The experimental data show that the formation of calcium hydroxide starts with the association of ions into complexes and clusters, which subsequently coalesce to form amorphous nanoparticles – much like what has been observed in the case of calcium carbonate and other prominent minerals. Subsequently, these particles aggregate and build networks, which eventually transform into hexagonal Ca(OH)2 crystals. The presence of a soluble polycarboxylate – as a known inhibitor of portlandite crystallization – does not change the main characteristics of this multistep nucleation pathway, but it proved capable of significantly extending the lifetime of the amorphous intermediate phase and thus delaying the transition to the final crystalline phase. Our observations confirm the notion that “non-classical” crystallization is a much more common phenomenon than initially believed – and that, for minerals forming in aqueous environments, it may actually be the rule rather than the exception.
KW - General Materials Science
KW - Building and Construction
PY - 2023
DO - https://doi.org/10.1016/j.cemconres.2023.107258
SN - 0008-8846
VL - 173
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-58162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
A1 - Omar, Hassan
A1 - Gawek, Marcel
A1 - Hertwik, Andreas
A1 - Madkour, Sherif
A1 - Schönhals, Andreas
T1 - Investigation of the behavior of thin polymeric films including the adsorbed layer on the substrate by nano-sized relaxation spectroscopy and complementary methods
N2 - Thin polymeric films are of great importance of high number of high-tech applications for instance in sensors and nanoelectronics. Form the scientific point of view thin films with thickness below 100 nm are ideal model systems to study confinement effects on its properties for instance on the molecular relaxation processes. In this contribution an overview is presented about the behavior of different systems as investigated by nanosized relaxation spectroscopy like broadband dielectric spectroscopy employing nano structured capacitors and AC chip calorimetry complimented by ellipsometry. The systems considered are PVME1, PVME/PS blends2,3 P2VP4, PBAC5 and polysulfone6. Besides the film also the adsorbed layer on the substrate prepared by a leaching approach and investigated by AFM is considered.1,4-7. For these investigationsss it is found that the adsorbed layer itself exhibits a relaxation dynamics which might be assigned either to molecular motions or to adsorptions desorption kinetics.
T2 - 9. International Discussion Meeting Relaxation Complex Systems
CY - Chiba, Japan
DA - 12.08.2023
KW - Thin polymer films
PY - 2023
AN - OPUS4-58103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Lothenbach, Barbara
ED - Carter, C. B.
T1 - Cement hydration mechanisms through time – a review
N2 - In this article the progress of the research on cement hydration mechanisms is critically reviewed, starting with the work of Le Chatelier and Michaelis during the late 19th century. Proposed mechanisms are discussed in the light of experimental data to highlight the role of new or improved analytical techniques. The focus of this article lies on the dormant period and the silicate reaction.
Today many of the mechanisms proposed throughout time cannot withstand experimental evidence and need to be rejected, including the classical protective hydrate layer theory. However, it seems likely that hydrated surface species are involved in the mechanism. Theories that aim to explain the rate changes solely based on the nucleation and growth of portlandite can also not withstand experimental evidence. Nevertheless, the retardation of portlandite crystal growth through silicate ions is a relevant factor. Especially since it might present a mechanism for the nucleation of calcium silicate hydrate (C-S-H), backing up theories that propose C-S-H and portlandite to grow from the same nuclei.
Finally, an overview over facts, that are currently considered to be valid and hence need to be regarded in future mechanisms is given.
KW - Cement hydration
KW - Calcium silicate hydrate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577460
DO - https://doi.org/10.1007/s10853-023-08651-9
SN - 1573-4803
VL - 58
IS - 24
SP - 9805
EP - 9833
PB - Springer Science + Business Media B.V
CY - Dordrecht [u.a.]
AN - OPUS4-57746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Friedrich, J.
T1 - Structure of plasma deposited acrylic acid‐allyl alcohol copolymers
N2 - Copolymer thin films with two types of functional groups have excellent performance as sensors, for example. The formation and deposition of allyl alcohol‐acrylic acid copolymer films by pulsed high frequency plasma is a complex process. As usual, the chemical composition of the top surface of the films was investigated by XPS and FTIR measurements. Furthermore, contact angle measurements with water were used to characterise the hydrophilicity and wettability of the polymer films.
After plasma deposition, a significant decrease in functional groups (OH and COOH) was observed compared to the classically copolymerised equivalent.
The remaining functional groups, i.e. the majority of these groups, were sufficient for application as sensor layers. Segmental mobility and conductivity, important for sensor applications, were analysed by broadband dielectric spectroscopy.
KW - Plasma Polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578349
DO - https://doi.org/10.1002/ppap.202300071
SN - 1612-8850
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-57834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Unwanted X-ray emission in ultrashort pulse laser processing: From metallic to biological materials
N2 - Ultrashort laser pulses have become established in many industrial processes. Additionally, they are also an integral part of medical applications especially in ophthalmology and to some extent in dentistry. The availability of highly repetitive powerful laser sources and advanced laser beam control systems have favored these developments. However, the laser processing may be accompanied by the generation of unwanted X-rays. Small doses per laser pulse can accumulate to significant dose levels at high laser pulse repetition rates. Moreover, burst mode processing increases the X-ray dose rates compared to single pulse use and results in X-ray photon energies up to 40 keV for tungsten targets. For laser treatment of human teeth, clearly noticeable X-ray skin dose rates can be found. The paper summarizes the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser processing in air.
T2 - Lasers in Manufacturing 2023 (LiM 2023)
CY - Munich, Germany
DA - 26.06.2023
KW - Ultrashort laser pulses
KW - Laser-induced X-ray emission
KW - Secondary hazard
PY - 2023
AN - OPUS4-57816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, D.
A1 - Megha, S. N.
A1 - Kiran, M. S. R. N.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Designing the Mechanical Plasticity of Benzylidene Indanones Based Molecular Crystals by Crystal Engineering
N2 - Mechanically flexible molecular crystals have important implications in flexible optoelectronics, optical waveguides, etc. We report a series of 2-benzylidene 1-indanone based plastic crystals. Moreover, we have shown how plasticity can be fine-tuned through controlling intermolecular interactions.
KW - Mechanical flexibility
KW - Organic crystal
KW - Mechanical property
PY - 2023
DO - https://doi.org/10.1021/acs.cgd.2c01137
SN - 1528-7483
VL - 23
SP - 657
EP - 661
PB - ACS Publications
AN - OPUS4-57773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
A1 - Stawski, Tomasz
T1 - Crystallization study of transition metal phosphates: Characterization of a non-classical crystallization pathway
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications.
T2 - HZB Usermeeting 2023
CY - Berlin, Germany
DA - 22.06.2023
KW - Struvite
KW - Transition metal
KW - Phosphates
KW - Crystallization
KW - Amorphous phases
PY - 2023
AN - OPUS4-57775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Crystallization study of transition metal phosphates: A novel example for non-classical crystallization theory
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.) which contain high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants . Typically, separate pathways have been considered to extract hazardous and transition metals or phosphate as critical raw materials, independently from each other. Here, we report the synthesis routes for transition metal phosphate (TMP) compounds (M3(PO4)2∙8H2O, NH4MPO4∙6H2O, M = Ni2+, Co2+, M-struvite and M-phosphate octahydrate), which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters could be a promising P-recovery route. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMP could be controlled. Detailed investigations of the precipitation process using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases which subsequently aggregate and condense to final crystals after extended reaction times. However, the reaction kinetics of the formation of a final crystalline product vary significantly depending on the metal cation(s) involved in the precipitation process. The occurring amorphous nanophases seem to majorly influence the outcome of crystallization. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The observed various degree of stability could be linked to the octahedral metal coordination environment. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications 4.
T2 - GeoMin Köln Konferenz 2022
CY - Cologne, Germany
DA - 11.09.2022
KW - Non-classical crystallization theory
KW - Amorphous phases
KW - Transition metal
KW - Phosphates
KW - Diffraction
PY - 2022
UR - https://www.geominkoeln2022.de/programme.html
AN - OPUS4-55874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Amariamir, Sasan
A1 - Benner, Philipp
A1 - George, Janine
T1 - Prediction of materials synthesizability
N2 - In the pursuit of discovering materials with desirable properties, extending the available material libraries is crucial. High-throughput simulations have become an integral part in designing new materials in the past decades. However, there is no straightforward way of distinguishing synthesizable materials from all the proposed candidates. This project focuses on employing AI-driven methods to estimate synthesizability of materials.
Up to now, material scientists and engineers have relied on domain knowledge as well as empirical heuristics to guess the stability and synthesizability of molecules and crystals. The famous Pauling rules of crystal stability are an example of such heuristics. However, after the accelerating material discovery in all the years since Pauling, these rules now fail to account for the stability of most known crystals. A new predictive set of heuristics for crystal stability/synthesizability is unlikely to be uncovered by human perception, given the magnitude and dimensionality of crystallographic data. Hence, a data-driven approach should be proposed to find a predictive model or set of heuristics which differentiate synthesizable crystal structures from the rest. The main challenge of this research problem is the lack of a negative set for classification. Here, there are two classes of data: the positive class which contains synthesizable materials and the negative class which contains materials which are not synthesizable. While the data from the positive class is simply the data of crystals which have been experimentally synthesized, we do not have access to data points which are certainly unsynthesizable. Strictly speaking, if an attempt of synthesizing a crystal fails, it does not necessarily follow that the crystal is not synthesizable. Also, there is no database available which contains the intended crystal structures of unsuccessful synthesis attempts.
This project proposes a semi-supervised learning scheme to predict crystal synthesizability. The ML model is trained on experimental and theoretical crystal data. The initial featurization focuses on local environments which is inspired by the Pauling Rules. The experimental data points are downloaded through the Pymatgen API from the Materials Project database which contains relaxed structures recorded in Inorganic Crystal Structure Database – ICSD. The theoretical data is queried from select databases accessible through the Optimade project’s API.
T2 - MSE Congress 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Synthesizability
KW - PU Learning
KW - Cheminformatics
PY - 2022
AN - OPUS4-56731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
T1 - The SPONGE v.1.0.0: Modeling scattering of shapes by STL input, with absolute intensities and size distribution.
N2 - Simulates X-ray and Neutron scattering patterns from arbitrary shapes defined by STL files.
Features:
- Uses multithreading to compute a number of independent solutions, then uses the variance of the results to estimate an uncertainty on the output.
- Can be launched from the command line using an excel sheet to define settings, or from a jupyter notebook.
- Outputs scattering patterns in absolute units if the contrast is set.
- A Gaussian size distribution is available, where the relative scaling of objects for each repetion can be varied. Recommended to be used with limited width (max. 10%) to avoid artefacts.
- Writes results with settings to an archival HDF5 file.
Application examples:
This software has been used in several studies to date. For example, it has been used here to simulate a model scattering pattern for a cuboid shape, which was then fed forward into the McSAS3 analysis program for analyzing scattering patterns of polydisperse cuboids. A second use is here, where it was used for the modeling of flattened helices. In this paper, scattering pattern features could be matched with particular morphological changes in the structure. Lastly, this paper has an example where it was used to validate the analytical analysis model, and explore the realistic limits of application of the analytical model.
KW - Software
KW - Scattering pattern analysis
KW - Scattering pattern simulation
KW - X-ray
KW - Neutron
KW - Command-line interface
KW - Scattering pattern
KW - STL file input
KW - Python
KW - Arbitrary shapes
PY - 2023
DO - https://doi.org/10.6084/m9.figshare.21857130.v1
PB - Digital Science
CY - Cambridge, MA, USA
AN - OPUS4-56815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
T1 - Accessing radiation damage to biomolecules on the nanoscale by particle-scattering simulations
N2 - Radiation damage to DNA plays a central role in radiation therapy to cure cancer. The physico-chemical and biological processes involved encompass huge time and spatial scales. To obtain a comprehensive understanding on the nano and the macro scale is a very challenging tasks for experimental techniques alone. Therefore particle-scattering simulations are often applied to complement measurements and aide their interpretation, to help in the planning of experiments, to predict their outcome and to test damage models. In the last years, powerful multipurpose particle-scattering framework based on the Monte-Carlo simulation (MCS) method, such as Geant4 and Geant4-DNA, were extended by user friendly interfaces such as TOPAS and TOPAS-nBio. This shifts their applicability from the realm of dedicated specialists to a broader range of scientists. In the present review we aim to give an overview over MCS based approaches to understand radiation interaction on a broad scale, ranging from cancerous tissue, cells and their organelles including the nucleus, mitochondria and membranes, over radiosensitizer such as metallic nanoparticles, and water with additional radical scavenger, down to isolated biomolecules in the form of DNA, RNA, proteins and DNA-protein complexes. Hereby the degradation of biomolecules by direct damage from inelastic scattering processes during the physical stage, and the indirect damage caused by radicals during the chemical stage as well as some parts of the early biological response is covered. Due to their high abundance the action of hydroxyl radicals (•OH) and secondary low energy electrons (LEE) as well as prehydrated electrons are covered in additional detail. Applications in the prediction of DNA damage, DNA repair processes, cell survival and apoptosis, influence of radiosensitizer on the dose distribution within cells and their organelles, the study of linear energy transfer (LET), the relative biological effectiveness (RBE), ion beam cancer therapy, microbeam radiation therapy (MRT), the FLASH effect, and the radiation induced bystander effect are reviewed.
KW - DNA
KW - Protein
KW - G5P
KW - OH
KW - Au
KW - AuNP
KW - Radiation
KW - SSB
KW - DSB
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - Particle scattering
KW - Penelope model
KW - Proteins
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Radiotherapy
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
KW - Base damage
KW - Base loss
KW - DNA radiation damage
KW - Direct damage
KW - Dissociative electron attachment (DEA)
KW - Dissociative electron transfer (DET)
KW - Double-strand break (DSB)
KW - ESCA
KW - Hydrated DNA
KW - Hydrated electron
KW - Hydration shell
KW - Hydroxyl radical
KW - Indirect damage
KW - Ionization
KW - Ionisation
KW - NAP-XPS
KW - Near ambient pressure xray photo electron spectroscopy
KW - Net-ionization reaction
KW - Prehydrated electron
KW - Presolvated electron
KW - Quasi-direct damage
KW - ROS
KW - Radical
KW - Reactive oxygen species
KW - Single-strand break (SSB)
KW - XPS
KW - Xray
KW - Xray photo electron spectrocopy
KW - Cosolute
KW - Ectoin
KW - Ectoine
KW - GVP
KW - Gene five protein
KW - Hydroxyectoine
KW - Ionizing radiation damage
KW - OH radical scavenger
KW - Monte-Carlo simulations
KW - Nanodosimetry
KW - Osmolyte
KW - Particle scattering simulations
KW - Protein unfolding
KW - Radical Scavenge
KW - Radical scavenger
KW - Single-stranded DNA-binding proteins
KW - SAXS
KW - Bio-SAXS
KW - X-ray scattering
KW - ssDNA
KW - dsDNA
KW - FLASH effect
KW - Bystander effect
KW - Ion beam therapy
KW - Bragg peak
KW - LET
KW - MCNP
KW - Photons
KW - Electrons
KW - Carbon ions
KW - MRT
KW - RNA
KW - RBE
KW - base loss
KW - abasic side
KW - DMSO
KW - Cells
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573240
DO - https://doi.org/10.1088/2399-6528/accb3f
SN - 2399-6528
VL - 7
IS - 4
SP - 042001
PB - Institute of Physics (IOP) Publishing
CY - London
AN - OPUS4-57324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Strahlenexpositionen bei der Anwendung von Ultrakurzpulslasern in der Medizin
N2 - Die Erzeugung unerwünschter Röntgenstrahlung bei der Ultrakurzpulslaser-Bearbeitung von Cornea und Zahnmaterial wurde untersucht. Laser-induzierte Dosisleistungen über dem natürlichen Hintergrund wurden gemessen. Mögliche Strahlenexpositionen in realen Anwendungen am Menschen wurden im Online-Vortrag diskutiert. Im Rahmen des vom BfS geförderten Projektes haben die Hochschule Mittweida und die BAM gemeinsam Untersuchungen durchgeführt.
T2 - Kolloquium des Bundesamtes für Strahlenschutz (BfS)
CY - Online meeting
DA - 18.04.2023
KW - Ultrakurzpulslaser
KW - Laser-induzierte Röntgenstrahlung
KW - Medizinische Anwendung
KW - Auge
KW - Zahn
PY - 2023
AN - OPUS4-57362
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Suppressed Transition and Dynamic self-asembly of ionic superdiscs in cylindrical nanochannels
N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing phase transition behaviors and relaxation dynamics. Here, we investigate the molecular mobility and electrical conductivity of a columnar ionic liquid crystal confined in self-ordered nanoporous alumina oxide membranes of pore size ranging from 180 nm down to 25 nm. We use nano-broadband dielectric spectroscopy (BDS) and calorimetry to study the dynamics and phase behavior. Calorimetric investigation reveals a complete suppression of the columnar – isotropic transition, while the plastic crystalline – columnar transition temperature decreases with inverse pore size and deviates from the Gibbs – Thomson equation.
For the bulk case, BDS detects two relaxation modes in the crystalline phase, the γ relaxation and the α1 relaxation, and two relaxation modes in the columnar phase, the α2 and α3 relaxation. All relaxation modes slow down for the confined case compared to the bulk. However, a new relaxation mode reflecting the interfacial layer emerges for the 80 and 25 nm. We discuss the possible molecular origins of the different relaxation modes observed. For the bulk ILC, a clear jump of 4 orders of magnitude in the absolute values of DC conductivity occurs at the transition from the plastic crystalline to hexagonal columnar phase, for the confined ILC, this transition is smooth. DC conductivity is reduced for the confined case, except for the 25nm, where the values are similar to the bulk.
T2 - APS March Meeting 2023
CY - Las Vegas, NV, USA
DA - 05.03.2023
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2023
AN - OPUS4-57342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krauss, S. W.
A1 - Eckardt, M.
A1 - Will, J.
A1 - Spiecker, E.
A1 - Siegel, R.
A1 - Dulle, M.
A1 - Schweins, R.
A1 - Pauw, Brian Richard
A1 - Senker, J.
A1 - Zobel, M.
T1 - H-D-isotope effect of heavy water affecting ligand-mediated nanoparticle formation in SANS and NMR experiments
N2 - An isotopic effect of normal (H2O) vs. heavy water (D2O) is well known to fundamentally affect structure and chemical properties of proteins, for instance. Here we correlate results from small angle X-ray and neutron scattering (SAXS, SANS) with high-resolution scanning transmission electron microscopy to track the evolution of CdS nanoparticle size and crystallinity from aqeuous solution in presence of the organic ligand ethylenediaminetetraacetate (EDTA) at room temperature in both H2O and D2O. We provide evidence via SANS experiments that exchanging H2O by D2O impacts nanoparticle formation by changing the equilibria and dynamics of EDTA clusters in solution as investigated by nuclear magnetic resonance. The colloidal stability of the CdS nanoparticles, covered by a layer of [Cd(EDTA)]2- complexes, is significantly reduced in D2O despite the strong stabilizing effect of EDTA in suspensions of normal water. Hence, conclusions about nanoparticle formation mechanisms from D2O solutions can bare limited transferability to reactions in normal water due to isotopic effects, which thus need to be discussed for contrast match experiments.
KW - General Materials Science
KW - Quantum dots
KW - CdS
KW - Deuterium
KW - X-ray scattering
KW - MOUSE
PY - 2023
DO - https://doi.org/10.1039/D3NR02419A
SN - 2040-3364
VL - 15
IS - 40
SP - 16413
EP - 16424
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Sokolowski‐Tinten, Klaus
T1 - Probing Laser‐Driven Structure Formation at Extreme Scales in Space and Time
N2 - Irradiation of solid surfaces with high intensity, ultrashort laser pulses triggers a variety of secondary processes that can lead to the formation of transient and permanent structures over a large range of length scales from mm down to the nano‐range. One of the most prominent examples are LIPSS – Laser‐Induced Periodic Surface Structures. While LIPSS have been a scientific evergreen for of almost 60 years, experimental methods that combine ultrafast temporal with the required nm spatial resolution have become available only recently with the advent of short pulse, short wavelength free electron lasers. Here, the current status and future perspectives in this field are discussed by exploiting the unique possibilities of these 4th‐generation light sources to address by time‐domain experimental techniques the fundamental LIPSS‐question, namely why and how laser irradiation can initiate the transition of a “chaotic” (rough) surface from an aperiodic into a periodic structure.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Free electron laser
KW - Pump-probe experiments
KW - Time-resolved scattering
KW - Capillary waves
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595048
DO - https://doi.org/10.1002/lpor.202300912
SN - 1863-8899
VL - 18
SP - 1
EP - 11
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-59504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Characterisation of thin layers of Polydopamine used as functional coatings in X-Ray optics
N2 - Polydopamine (PDA) is a biological / biomimetic polymer which has spiked considerable interest in recent years. Its monomer is an important neurotransmitter and it is one of the strongest glues produced by biological organisms. Polydopamine is a candidate for several applications, mainly in the field of biology and medicine, but also - recently - for layer coatings with optical, electrical, and mechanical function.
In this work, we investigate PDA layers intended as reflectivity enhancers for mirror surfaces in X-ray astronomical observatories. It has previously been shown, that such X-ray telescopes can be improved by a coating of PDA in the thickness range of several nm. Accurate thickness determination is required to monitor and optimise the coating process. We use spectroscopic ellipsometry to determine first the dielectric function of the polydopamine layers using model coatings of sufficient thickness. This data is then used to accurately determine the layer thickness of much thinner PDA layers. This study resulted in data on the thickness and dielectric function of PDA layers that could lead to a better understanding of the correlation of layer thickness and layer properties depending on the process parameters.
T2 - Deutsche Physikalische Gesellschaft - Frühjahrstagung
CY - Berlin, Germany
DA - 17.03.2024
KW - Ellipsometry
KW - Polydopamine
KW - Thin Polymer Layers
KW - X-Ray Reflectometry
KW - Biopolymers
PY - 2024
AN - OPUS4-59760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Everything SAXS Part 1: Introduction, Sample Requirements and Measurement "Space"
N2 - This talk for the Swiss Society for Crystallography (SSCr) workshop on SAXS will introduce scattering from various angles, focusing in particular on:
- Information content of X-ray scattering experiments, three entry points…
- An introduction to Fourier Transforms
- Sample criteria, compatibility, and selection
- Key indicators of a measurement – where is the information?
- Key indicators of measurement quality
- Experiment planning, the basics
T2 - Topical workshop of the Swiss Society for Crystallography
CY - Zurich, Switzerland
DA - 08.09.2023
KW - X-ray scattering
KW - Data stewardship
KW - Measurement science
KW - MOUSE
KW - Holistic experiment approaches
PY - 2023
AN - OPUS4-58235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Everything SAXS Part 2: Data Processing, Workflow and Pitfalls
N2 - The second talk for the Swiss Society for Crystallography (SSCr) workshop on SAXS will highlight the data processing challenges, holistic experimental workflow developments, and the pitfalls. In particular, the following items will be addressed:
- The importance of data processing and estimating uncertainty
- A universal correction pipeline – away with the headaches, at least for this step!
- Experiment planning part 2, some tips and advice to improve your corrected data.
- Sample preparation, background selection, some tips and advice to improve your corrected data.
- Automate for your mental well-being; electronic logbooks, measurement catalogs and workflow management software
- Life on the edge: several pitfalls to avoid…
T2 - Topical workshop of the Swiss Society for Crystallography
CY - Zurich, Switzerland
DA - 08.09.2023
KW - X-ray scattering
KW - MOUSE
KW - Data processing
KW - Uncertainties
KW - Pitfalls
PY - 2023
AN - OPUS4-58236
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Determining thermal transitions in thin polymer layers by means of spectroscopic ellipsometry
N2 - Thin polymer layers have enormous technical significance as polymer coatings on materials are very cost-effective for tailoring properties of surfaces. Apart from technical aspects in their use, thin polymer layers can be used to determine dimensional aspects in properties of material, such as confinement effects.
In this work, we investigated several different polymer layer materials and determined their glass transition region by means of temperature-dependent spectroscopic ellipsometry. We have optimised our fitting procedure of the ellipsometric data produced in temperature ramp experiments. By this, we could measure the dependence of Tg on the layer thickness in a wide variety of thickness values, proving the existence of confinement effects in the investigated systems. We compare numerical methods for determining the location of the glass transition and discuss the possibilities of different analysis methods when determining thermal transitions. We also discuss the simultaneous existence of these transitions and annealing effects and the implications on the accuracy of the determined data.
T2 - 12th Workshop Ellipsometry 2023
CY - Prague, Czech Republic
DA - 18.09.2023
KW - Thin Films
KW - Polymers
KW - Ellipsometry
KW - Themal Transitions
PY - 2023
AN - OPUS4-58413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardes, C. E. S.
A1 - Feliciano, I.O.
A1 - Naese, Christoph
A1 - Emmerling, Franziska
A1 - Minas da Piedade, M.
T1 - Energetics of dehydroepiandrosterone polymorphs I and II from solution and drop-sublimation Calvet microcalorimetry measurements
N2 - The lattice enthalpies and monotropic relationship of two dehydroepiandrosterone (DEHA) polymorphs (forms I and II) were evaluated through a combination of differential scanning calorimetry (DSC), isothermal solution microcalorimetry, and drop-sublimation Calvet microcalorimetry experiments. The standard molar enthalpy of transition between both forms was determined as ΔtrsHom (II→I, 298.15 K) = - 0.90 ± 0.07 kJ mol-1 and ΔtrsHom (II→I, 417.8 K) = - 1.7 ± 1.0 kJ mol- 1, from measurements of standard molar enthalpies of solution in dimethyl sulfoxide and enthalpies of fusion, respectively. Drop-sublimation Calvet microcalorimetry experiments on form I led to ΔsubHom (cr I, 298.15 K) = 132.0±3.3 kJ mol - 1. This result, when combined with the more precise ΔtrsHom (II→I) value obtained by solution calorimetry, afforded ΔsubHom (cr II, 298.15 K) = 131.1±3.3 kJ mol - 1. The overall data indicate that on enthalpic grounds form I is more stable than form II from 298.15 K up to fusion. This conclusion, and the fact that DSC experiments indicated that form I has also a considerably higher temperature fusion, namely, Tfus(cr I)= 422.5±0.2 K and Tfus(cr II) = 413.1±0.2 K, suggest that the two polymorphs are monotropically related.
KW - Calorimetry
KW - Polymorphism
KW - Enthalpy of solution
KW - Enthalpy of sublimation
KW - Thermochemistry
KW - Lattice enthalpy
PY - 2023
DO - https://doi.org/10.1016/j.jct.2023.107137
SN - 0021-9614
SN - 1096-3626
VL - 186
SP - 1
EP - 7
PB - Elsevier
AN - OPUS4-58418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Chewle, S.
A1 - Weber, M.
T1 - Revealing Kinetics of Paracetamol Crystallization Using Time Resolved Raman Spectroscopy, Orthogonal Time-Lapse Photography, and Non-Negative Matrix Factorization (OSANO)
N2 - Crystallization is a complex phenomenon with farreaching implications for the production and formulation of active pharmaceutical ingredients. Understanding this process is critical for achieving control over key physicochemical properties that can affect, for example, the bioavailability and stability of a drug. In this study, we were able to reveal intricate and diverse dynamics of the formation of metastable intermediates of paracetamol crystallization varying with the choice of solvent. We demonstrate the efficacy of our novel approach utilizing an objective function-based non-negative matrix factorization technique for the analysis of time-resolved Raman
spectroscopy data, in conjunction with time-lapse photography.
Furthermore, we emphasize the crucial importance of integrating Raman spectroscopy with supplementary experimental instrumentation for the mathematical analysis of the obtained spectra.
KW - Polymorphism
KW - Crystallization
KW - Measurement
KW - Algorithm
PY - 2023
DO - https://doi.org/10.1021/acs.cgd.3c00617
SN - 1528-7483
VL - 23
SP - 6737
EP - 6746
PB - ACS Publications
AN - OPUS4-58193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, Deepak
A1 - Ranjan, Subham
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Takamizawa, Satoshi
A1 - Ghosh, Soumyajit
T1 - Elasto-plastic behaviour with reversible thermosalient expansion in acrylonitrile-based organic crystals
N2 - Crystalline materials that exhibit reversible mechanical responses upon exposure to external stimuli have garnered significant attention owing to their potential applications in various fields. Herein, we report a crystal of (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(4-bromophenyl)acrylonitrile) (DSBr), which displays simultaneous elasto-plastic behaviour and reversible thermosalient effects. While elasto-plastic behaviour is attributed to underlying packing features, reversible thermosalient expansion is attributed to uniaxial expansion mediated by heat. Exceptional length increase and contraction upon cooling is due to the restorative nature of weak interactions through a cooperative effect. The cooperative movement of molecules is reflected in the unidirectional expansion of the habit plane. Thermosalient reversible expansion–contraction in elasto-plastic crystals have not been discussed in the literature so far. Detailed analysis reported herein provides a comprehensive understanding of the underlying mechanism of flexibility and thermosalient responses. This crystal's unique blend of reversible thermal expansion with flexibility holds substantial promise for applications in flexible thermal actuators.
KW - Materials Chemistry
KW - General Chemistry
PY - 2024
DO - https://doi.org/10.1039/D3TC04272C
SN - 2050-7526
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Gefährdung durch Röntgenemission bei der UKP-Laser-Materialbearbeitung
N2 - Der Vortrag gibt einen Überblick zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und der dabei ggf. auftretenden unerwünschten Röntgenstrahlung. Es wird die Laserbearbeitung von technischen und biologischen Materialien diskutiert. Schutzmöglichkeiten gegenüber der Röntgenstrahlung werden erörtert.
T2 - Sonthofer Strahlenschutztage 2024
CY - Sonthofen, Germany
DA - 11.03.2024
KW - Ultrakurzpulslaser
KW - Laser-induzierte Röntgenstrahlung
KW - Materialbearbeitung
KW - Technische Materialien
KW - Biologische Anwendungen
PY - 2024
AN - OPUS4-59667
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
T1 - Trinamic TMCL IOC for exposing Trinamics motor controllers to EPICS CA
N2 - Trinamic TMCL IOC is a Python package designed for controlling stepper motors connected to a Trinamic board using the TMCL language (all boards supported by PyTrinamic should now work, has been tested on the TMCM 6110 and the TMCM 6214). Since it is implementing the TMCL protocol, it should be easy to adapt to other Trinamic motor controller boards. This package assumes the motor controller is connected over a machine network via a network-to-serial converter, but the underlying PyTrinamic package allows for other connections too.
This allows the control of attached motors via the EPICS Channel-Access virtual communications bus. If EPICS is not desired, plain Pythonic control via motion_control should also be possible. An example for this will be provided in the example.ipynb Jupyter notebook.
This package leverages Caproto for EPICS IOCs and a modified PyTrinamic library for the motor board control, and interfaces between the two via an internal set of dataclasses. Configuration for the motors and boards are loaded from YAML files (see tests/testdata/example_config.yaml).
The modifications to PyTrinamic involved extending their library with a socket interface. This was a minor modification that should eventually find its way into the official package (a pull request has been submitted).
KW - Instrumentation
KW - Motor controller
KW - EPICS
KW - Channel access
KW - Instrument control
KW - Laboratory automation
PY - 2024
DO - https://doi.org/10.5281/zenodo.10792593
PB - Zenodo
CY - Geneva
AN - OPUS4-59624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
T1 - Imaging spectroscopic ellipsometry for investigation of energy materials and materials for nano-electronics
N2 - Ellipsometry is a very powerful tool used for accurate material investigation in a wide wavelength range. It is a non-destructive and fast method. Imaging ellipsometry as a combination of optical microscopy and ellipsometry enables spatially resolved measurements when determining the layer thickness and dielectric properties of thin layers. It is known for its high polarisation sensitivity and high contrast for the surface structures. In this contribution we show the application of the imaging ellipsometry for detection of defects in energy materials and quality validation of possible reference materials for nano-electronics.
Defects in wide bandgap semiconductors, in homoepitaxial SiC and heteroepitaxial GaN layers on transparent SiC substrates, can be successfully detected and classified by means of imaging ellipsometry. Correlation of imaging ellipsometry results with results from complementary techniques such as white light interference microscopy as well as atomic force microscopy contribute to understanding of surface topography and defect formation mechanisms. We discuss the potential of different methods for analysing ellipsometric map data for monitoring the defect densities.
Electric properties of materials at the nanoscale can be investigated by means of scanning probe microscopy methods such as scanning microwave microscopy and conductive atomic force microscopy. However, development of new robust and easy-to-use calibration methods and calibration standards is essential to increase the traceability of these methods and allow their broad application in industry. We show how imaging spectroscopic ellipsometry can be used for development and monitoring of processing quality of patterned reference samples based on indium tin oxide (ITO) layer with different thickness and conductivity.
T2 - 12th Workshop on Spectroscopic Ellipsometry (WSE)
CY - Prague, Czech Republic
DA - 18.09.2023
KW - Ellipsometry
KW - Thin Films
KW - Transparent Conductive Oxides
KW - Energy materials
KW - White light interference microscopy
KW - Nanoelectronics
KW - Wide-bandgap semiconductors
PY - 2023
AN - OPUS4-59340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Röntgenstrahlungsexposition bei der Anwendung von Ultrakurzpulslasern in der Medizin
N2 - Die Laserbearbeitung von Materialien mit ultrakurzen Laserpulsen kann zu einer sekundären Emission gefährlicher Röntgenstrahlen führen. Dieser Effekt wurde bisher bei der Bearbeitung von technischen Materialien wie Metallen beobachtet. Die Röntgenemission bei der abtragenden Bearbeitung von biologischen Geweben ist noch weitgehend unerforscht. Der Vortrag präsentiert erste Untersuchungen und Ergebnisse des radiologischen Gefährdungspotentials bei der medizinischen Anwendung von Ultrakurzpulslasern am Menschen.
T2 - Bayerische Laserschutztage 2024
CY - Nuremberg, Germany
DA - 17.01.2024
KW - Ultrakurzpulslaser
KW - Laser-induzierte Röntgenstrahlung
KW - Medizinische Anwendung
KW - Auge
KW - Zahn
PY - 2024
AN - OPUS4-59399
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goswami, Juli Nanda
A1 - Haque, Najirul
A1 - Seikh, Asiful H.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Bar, Nimai
A1 - Ifseisi, Ahmad A.
A1 - Biswas, Surajit
A1 - Dolai, Malay
T1 - Carboxylative cyclization of propargyl alcohols with carbon dioxide for the synthesis of α-alkylidene cyclic carbonates in presence of Co(III) schiff base complex catalyst
N2 - A cobalt(III) complex, [Co(L)3](DMF) (1) of Schiff base ligand HL, 2-((E)-(benzylimino)methyl)-4-bromophenol is prepared and single crystal X-ray structural analysis have also been performed. The structures of complex 1 showed hexa-coordinated mononuclear systems that adopt octahedral geometry. The complex has also exhibited the supramolecular networks through non-covalent interactions like H-bonding, C–Hπ stacking. Moreover, the complex 1 is very effective in the catalytic fixation of carbon dioxide in propergyl alcohols to produce α-alkylidene cyclic carbonates. The catalytic production of α-alkylidene cyclic carbonates have been carried out through carboxylative cyclization of propargyl alcohols using CO2 balloon of 1 atm pressure at 80 ◦C. Solvent free condition (green synthesis) made this catalytic protocol eco-friendly towards the environment. Utilizing various substrates of propargyl alcohols moderate to high percentage yield (62–95%) of respective α-alkylidene cyclic carbonates product have been isolated over this catalytic reaction. Besides, the theoretical calculations (DFT) was performed for the prediction of probable mechanism of the catalytic reaction
KW - Catalytic fixation of carbon dioxide
KW - Carboxylative cyclization of propargyl alcohols
KW - Cobalt (III) Schiff base complex
KW - X-ray crystal analysis
PY - 2024
DO - https://doi.org/10.1016/j.molstruc.2023.136868
SN - 0022-2860
VL - 1296
IS - Part 1
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-58947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Why shaken, not stirred, makes the difference: insights into mechanochemical reactions from in situ investigations
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (poly-morphic) cocrystals[1,3], metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results.
Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - GdCh Vortrag Universität Potsdam
CY - Potsdam, Germany
DA - 05.06.2023
KW - Mechanochemistry
KW - In Situ
PY - 2023
AN - OPUS4-58982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Combination of complementary methods For in situ studies
N2 - This talk explores the synergistic application of complementary synchrotron methods for in situ investigations, providing a comprehensive approach to enhance analytical capabilities in materials research and characterization.
T2 - INSYNX - DEUTSCH-BRASILIANISCHER WORKSHOP ON BREAKING BOUNDARIES OF IN SITU SYNCHROTRON X-RAY METHODS
CY - Sao Paulo, Brazil
DA - 06.03.2023
KW - In situ
KW - Synchrotron
PY - 2023
AN - OPUS4-59025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry has become a compelling method for producing (new) molecule s and mate-rials, but the inner workings of the milling jars remain a fascinating mystery. Advances in this field include tailor-made chemical systems and real-time revelations using techniques such as XRD and Raman spectroscopy.
This talk will discuss our recent progress in using X-ray diffraction and sophisticated spectros-copy to observe reactions in various material systems during ball milling and extrusion in real-time.
The complexity of mechanochemical reactions spans multiple scales and requires a holistic ap-proach. The categorisation of reactions by investigative methods precedes the exploration of real-time analysis that reveals macroscopic processes using synchrotron techniques.
During this exploration, one resounding realisation remains: We are on the threshold of under-standing. The complexity of mechanochemistry requires a collective effort, drawing on the ex-pertise of a diverse community. As we unravel the web of mechanochemical phenomena, we acknowledge the collaborative nature of this ongoing journey.
T2 - CMCC Mechanochemistry Discussions
CY - Online meeting
DA - 21.09.2023
KW - Mechanochemistry
KW - In situ
PY - 2023
AN - OPUS4-59026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Connecting the nodes: networks and networking
N2 - This talk explores the intricate connections between scientists, focusing on the networking dynamics within the realm of metal-organic frameworks (MOFs). The study delves into the collaborative networks formed among scientists, shedding light on the synergistic relationships that contribute to advancements in MOF research.
T2 - WINS School 2023 Frameworks and networks
CY - Blossin, Germany
DA - 02.06.2023
KW - Metal-organic frameworks
PY - 2023
AN - OPUS4-59028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witt, Julia
T1 - Exploring innovative Materials and in situ techniques
N2 - Presentation of some projects conducted in recent years related to corrosion studies and research on electrocatalysis. The talk was part of a seminar at the University of Toronto and took place within the framework of a scientific exchange stay.
T2 - Seminar at the University of Toronto
CY - Toronto, Canada
DA - 11.10.2023
KW - Multi-principal element alloys (MPEAs)
KW - Electrocatalysis
KW - Corrosion
KW - Materials acceleration platforms (MAPs)
PY - 2023
AN - OPUS4-59029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casali, Lucia
T1 - Use of the solvent-free mechanochemical method for a sustainable preparation of pharmaceuticals
N2 - With the growing interest in environmental issues on the part of governments and institutions, pharmaceutical industries are asked to reduce their environmental footprint. Given the major impact related to the use of solvents, the development of methodologies less solvent demanding is nowadays even more urgent. In light of that, mechanochemistry would be a suitable solvent-free technology since it promotes the activation of the chemical reactions between (generally) solid materials via inputs of mechanical energy. Since such reactions may occur outside the kinetic and thermodynamic rules of conventional solution chemistry, the main limit of mechanochemistry is the poor mechanistic understanding of the solid-state transformations involved, which is still hindering a widespread use of the method, as well a scale-up to the industrial level. However, the development of methods for real-time monitoring of the mechanochemical reactions enables obtaining (in)accessible information on reaction intermediates, new products, or reaction time, thus getting closer to a better understanding of the mechanistic behaviour. With the rules of this chemistry becoming increasingly clear, the new reaction pathways of mechanochemistry wouldn’t represent a limit anymore, but an asset, that may lead to lot of opportunities for the pharmaceutical industry.
T2 - Post Doc Day Berlin
CY - Berlin, Germany
DA - 02.11.2023
KW - Mechanochemistry
KW - Sustainability
KW - Pharmaceuticals
PY - 2023
AN - OPUS4-59010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry emerges as a potent, environmentally friendly, and straightforward approach for crafting novel multicomponent crystal systems. Various milling parameters, including milling frequency, time, filling degree of the milling jar, ball diameter, vessel size, degree of milling ball filling, and material of jars, are recognized influencers on the mechanisms and rates of product formation. Despite the growing interest in mechanochemistry, there exists a gap in understanding the mechanistic aspects of mechanochemical reactivity and selectivity. To address this, diverse analytical methods and their combinations, such as powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography, have been developed for real-time, in situ monitoring of mechanochemical transformations.
This discussion centers on our recent findings, specifically investigating the formation of (polymorphic) cocrystals and metal-organic frameworks. Through these studies, we aim to unravel the impact of milling parameters and reaction sequences on the formation mechanism and kinetics. Notably, in the mechanochemical chlorination reaction of hydantoin, normalizing kinetic profiles to the volume of the milling ball unequivocally demonstrates the conservation of milling reaction kinetics. In this ball-milling transformation, physical kinetics outweigh chemical factors in determining reaction rates. Attempting to interpret such kinetics solely through chemical terms poses a risk of misinterpretation. Our results highlight that time-resolved in situ investigations of milling reactions provide a novel avenue for fine-tuning and optimizing mechanochemical processes.
T2 - PhD Seminar
CY - Online meeting
DA - 12.10.2023
KW - Mechanochemistry
KW - In situ
PY - 2023
AN - OPUS4-59022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Investigating the mechanism and kinetics of the mechanochemical synthesis of multi-component systems
N2 - Mechanochemistry is a promising and environmentally friendly approach for synthesizing (novel) multicomponent crystal systems. Various milling parameters, such as milling frequency, milling time, and ball diameter have been shown to influence the mechanisms and rates of product formation. Despite increasing interest in mechanochemistry, there is still limited understanding of the underlying reactivity and selectivity mechanisms.
Various analytical techniques have been developed to gain insight into the mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy and thermography. Using these techniques, we have studied the formation of (polymorphic) cocrystals, organometallic compounds and salts, and elucidated the influence of milling parameters and reaction sequences on the formation mechanism and kinetics.
For example, our study of the mechanochemical chlorination reaction of hydantoin revealed that normalisation of the kinetic profiles to the volume of the grinding ball clearly showed that physical kinetics dominate the reaction rates in a ball-milling transformation. Attempts to interpret such kinetics in purely chemical terms risk misinterpretation of the results.
Our results suggest that time-resolved in situ investigation of milling reactions is a promising way to fine-tune and optimise mechanochemical processes.
T2 - ISIC 2023
CY - Glasgow, Scotland
DA - 05.09.2023
KW - Mechanochemistry
KW - Polymorphy
KW - In situ
PY - 2023
AN - OPUS4-59023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry emerges as a potent, environmentally friendly, and straightforward approach for crafting novel multicomponent crystal systems. Various milling parameters, including milling frequency, time, filling degree of the milling jar, ball diameter, vessel size, degree of milling ball filling, and material of jars, are recognized influencers on the mechanisms and rates of product formation. Despite the growing interest in mechanochemistry, there exists a gap in understanding the mechanistic aspects of mechanochemical reactivity and selectivity. To address this, diverse analytical methods and their combinations, such as powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography, have been developed for real-time, in situ monitoring of mechanochemical transformations.
This discussion centers on our recent findings, specifically investigating the formation of (polymorphic) cocrystals and metal-organic frameworks. Through these studies, we aim to unravel the impact of milling parameters and reaction sequences on the formation mechanism and kinetics. Notably, in the mechanochemical chlorination reaction of hydantoin, normalizing kinetic profiles to the volume of the milling ball unequivocally demonstrates the conservation of milling reaction kinetics. In this ball-milling transformation, physical kinetics outweigh chemical factors in determining reaction rates. Attempting to interpret such kinetics solely through chemical terms poses a risk of misinterpretation. Our results highlight that time-resolved in situ investigations of milling reactions provide a novel avenue for fine-tuning and optimizing mechanochemical processes.
T2 - Brimingham Green chemistry
CY - Birmingham, England
DA - 08.09.2023
KW - Mechanochemistry
KW - Green Chemistry
PY - 2023
AN - OPUS4-59024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, Deepak
A1 - Ahmad, Shamim
A1 - Tothadi, Srinu
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, Soumyajit
T1 - Linker size dependent mechanical properties of di-imine based molecular crystals
N2 - We have demonstrated the ability to modify the mechanical flexibility of molecular crystals by modulating the length of intervening linker moieties while keeping the terminal shape synthons the same.
KW - Mechanically flexible molecular crystals
KW - Mechanical properties
KW - Crystal Engineering
PY - 2023
DO - https://doi.org/10.1039/D3CE00928A
SN - 1466-8033
SP - 1
EP - 8
PB - RSC
CY - London
AN - OPUS4-58836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
A1 - Fähler, Sebastian
T1 - Thermomagnetic generators with magnetocaloric materials for harvesting low grade waste heat
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage.
Here we give an overview on our research, covering both materials and systems. We demonstrate that guiding the magnetic flux with an appropriate topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude. Through a combination of experiments and simulations, we show that a pretzel-like topology results in a sign reversal of the magnetic flux. This avoids the drawbacks of previous designs, namely, magnetic stray fields, hysteresis and complex geometries of the thermomagnetic material.
Though magnetocaloric materials had been the first choice also for thermomagnetic generators, they require some different properties, which we illustrate with Ashby plots for materials selection. Experimentally we compare La-Fe-Co-Si and Gd plates in the same thermomagnetic generator. Furthermore, we discuss corrosion and deterioration under cyclic use is a severe problem occurring during operation. To amend this, composite plates using polymer as a matrix have been suggested previously.
T2 - Dresden Days of Magnetocalorics
CY - Dresden, Germany
DA - 13.11.2023
KW - Thermomagnetic material
KW - Waste heat recovery
KW - Generator
PY - 2023
AN - OPUS4-58865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Ethics in research for PhD students
N2 - The talk gives a short overview and explains basic principles of research ethics for PhD students. We examine the most important principles in the codes of conduct for good scientific practice on EU and national level. Based on these general rules, we give some hands-on practical tips for daily scientific work and discuss in detail one of the fields most susceptible to conflict, the topic of authorship in scientific publications.
T2 - Kick-off meeting ITN USES2
CY - Online meeting
DA - 09.11.2023
KW - Research ethics
KW - PhD training
PY - 2023
AN - OPUS4-58783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
A1 - Osterwald, Stephan
A1 - Gerhold, Stefan
T1 - Mess- und Prüfverfahren für Schichten und Schichtsysteme - Der DIN-Normausschuss 062-01-61
N2 - Die Funktionalität von modernen technischen Komponenten liegt meist in der Oberfläche und in Beschichtungen. Das Design und die Herstellungsqualität von Beschichtungen ist essenziell für die optischen, elektrischen, mechanischen und chemischen Eigenschaften von Bauteilen, sowie für den Korrosions- und Verschleißschutz. In diesem Gremium bearbeiten wir Normen für die Qualitätssicherung von dünnen Schichten verschiedener Art. Dabei betrachten wir Eigenschaften wie Schichtdicke, Zusammensetzung, Haltbarkeit, Korrosionsbeständigkeit und physikalische Parameter von dünnen Schichten mit sehr vielfältigen Techniken. Neben klassischen Verfahren aus der Galvanik und Schichtmesstechnik, werden dabei auch neuere spektroskopische Verfahren wie Ellipsometrie und THz-Reflektion bedeutend. Unser Gremium ist offen für neue Mitglieder aus der Oberflächen- und Beschichtungsgemeinschaft.
T2 - ZVO Oberflächentage 2023
CY - Berlin, Germany
DA - 13.09.2023
KW - Dünne Schichten
KW - Galvanotechnik
KW - Metallschichten
KW - Messtechnik
PY - 2023
AN - OPUS4-58432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matamoros-Veloza, A.
A1 - Stawski, Tomasz
A1 - Vargas, S.
A1 - Neville, A.
T1 - Study of a Local Structure at the Interface between Corrosion Films and Carbon Steel Surface in Undersaturated CO2 Environments
N2 - Industries transporting CO2 gas-saturated fluids have infrastructures made of carbon steel. This is a good material with great mechanical properties but prone to corrosion and potential failure. Corrosion in sweet environments involves the formation of FeCO3 as a corrosion film, which is recognized to play a protective role under certain conditions. This work on the dissolution of corrosion films in sweet environments, under acidic and undersaturated conditions, demonstrates that the effects on the integrity of steel are far more significant than the damage observed on the surface of the corrosion film. Our results prove that dissolution of FeCO3 involved the presence of an amorphous phase, the intermediate formation of FeCl2 or FeCl+, and the presence of a phase with short distance atom–atom correlations. The amorphous phase was identified as a mixture of retained γ-Fe and Fe3C. Partially broken α-Fe and Fe3C structures were identified to prove the damage on the material, confirming the interface zone without evident damage on the corrosion film. Dissolution affected both the α-Fe and FeCO3, with the lattice [102̅] from the FeCO3 crystalline structure being the fastest to dissolve. The damage of steel at the molecular scale was evident at the macroscale with pit depths of up to 250 μm. The impact on the integrity of steel can be, therefore, more drastic than frequently reported in industrial operations of CO2 transport industries that use cleaning procedures (e.g., acid treatment, pigging) as part of their operational activities.
KW - Steel
KW - Corrosion
KW - Siderite
KW - Diffraction
KW - Pair distribution function
KW - Synchrotron
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572156
DO - https://doi.org/10.1021/acsomega.2c07631
SN - 2470-1343
VL - 8
IS - 9
SP - 8497
EP - 8504
PB - ACS
AN - OPUS4-57215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chambers, Aaron
T1 - Synthesis of ZIF nanoparticles with functionalisation towards effective composite formation
N2 - A presentation on functionalising ZIF-8 nanoparticles for composite formation. Characterisation data for the nanoparticles is shown.
T2 - Materials Chemistry Seminar
CY - Online meeting
DA - 23.02.23
KW - MOF composite
KW - Nanoparticles
KW - ZIF-8
PY - 2023
AN - OPUS4-57210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy, advanced calorimetry and Neutron Scattering
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n=5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations a γ-relaxation due to localized fluctuations as well as two glassy dynamics the αcore and αalkyl relaxation were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n=8 from a rigid constrained (n=5,6) to a softer system (n=10,12) on a molecular lenght scale was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition. The results were confirmed by in- and quasielastic neutron scattering
T2 - Confit 2022
CY - Grenoble, France
DA - 10.10.2022
KW - Glassy Dynamics
KW - Discotic Liquid Crystals
PY - 2022
AN - OPUS4-56661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced periodic surface structures: mechanisms, applications, and unsolved problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation.
From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc.
This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
Fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities to resolve laser-induced structure formation at surfaces on the sub-micrometer to nanometer length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. This unique spatio-temporal resolution allows to reveal early signatures of coherent/plasmonic electromagnetic scattering effects followed by the excitation of hydrodynamic capillary waves – providing new insights to the above-mentioned debate.
Finally, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. While the currently available laser and scanner technology already allows large area surface processing with rates at the m2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. Strategies for overcoming such limitations are outlined.
T2 - Institutskolloquium des Leibniz-Instituts für Oberflächenmodifizierung
CY - Leipzig, Germany
DA - 02.02.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Industrial applications
KW - Femtosecond laser
PY - 2023
AN - OPUS4-56949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, P.
A1 - Chakraborty, Gouri
A1 - Roeser, J.
A1 - Vogl, S.
A1 - Rabeah, J.
A1 - Thomas, A.
T1 - Integrating Bifunctionality and Chemical Stability in Covalent Organic Frameworks via One-Pot Multicomponent Reactions for Solar-Driven H2O2 Production
N2 - Multicomponent reactions (MCRs) can be used to introduce different functionalities into highly stable covalent organic frameworks (COFs). In this work, the irreversible three-component Doebner reaction is utilized to synthesize four chemically stable quinoline-4-carboxylic acid DMCR-COFs (DMCR-1−3 and DMCR-1NH) equipped with an acid−base bifunctionality. These DMCR-COFs show superior photocatalytic H2O2 evolution (one of the most important industrial oxidants) compared to the imine COF analogue (Imine-1). This is achieved with sacrificial oxidants but also in pure water and under an oxygen or air atmosphere. Furthermore, the DMCR-COFs show high photostability, durability, and recyclability. MCR-COFs thus provide a viable materials’ platform for solar to chemical energy conversion.
KW - Reactions
KW - Bifunctionality
KW - Postsynthetic modification
KW - Multicomponent
PY - 2022
DO - https://doi.org/10.1021/jacs.2c11454
SN - 0002-7863
VL - 145
IS - 5
SP - 2975
EP - 2984
PB - ACS Publications
AN - OPUS4-56922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Advanced Pulse Laser Machining Technology"
N2 - “Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications. This is significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts.
KW - Editorial
KW - Pulse Laser
KW - Laser Machining
KW - Ultrashort laser pulses
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568410
DO - https://doi.org/10.3390/ma16020819
SN - 1996-1944
VL - 16
IS - 2
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-56841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Krüger, Jörg
ED - Bonse, Jörn
T1 - Special Issue "Advanced Pulse Laser Machining Technology"
N2 - Advanced Pulse Laser Machining Technology is a rapidly growing field to tailor special industrial and scientific applications. This is significantly driven by the availability of high-repetition rate laser sources and novel beam delivery concepts.
This Special Issue focuses on developments in areas of surface and volume laser material processing, including spatial and temporal beam shaping, Bessel-beam dicing, direct laser interference patterning (DLIP), laser-induced forward transfer (LIFT), pulse burst machining, waveguide writing, and two-photon polymerization. Additionally, limitations of modern laser processing caused by failure of laser optics or unwanted secondary hazards like X-ray emission are addressed.
Here, we would like to attract contributors from industry and academics. This Special Issue shall bundle original research and review articles of the latest achievements.
KW - Advanced ultrashort-laser technology
KW - Bessel-beam laser dicing
KW - Direct laser interference patterning (DLIP)
KW - High-repetition rate ultrafast laser processing
KW - Laser-induced forward transfer (LIFT)
KW - X-ray hazards during ultrafast laser processing
KW - Volume processing, waveguide writing
KW - Temporal beam shaping for precision machining
PY - 2023
UR - https://www.mdpi.com/journal/materials/special_issues/pulse_laser_machining
SN - 1996-1944
PB - MDPI
CY - Basel
AN - OPUS4-56842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraft, Sebastian
A1 - Schille, J.
A1 - Bonse, Jörn
A1 - Löschner, U.
A1 - Krüger, Jörg
T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses
N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet.
Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays.
KW - Ultrashort pulsed laser
KW - Laser-induced X-ray emission
KW - Ophthalmology
KW - Dentistry
KW - Secondary hazard
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960
DO - https://doi.org/10.1007/s00339-023-06440-4
SN - 0947-8396
VL - 129
IS - 3
SP - 1
EP - 8
PB - Springer
AN - OPUS4-56996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macková, A.
A1 - Jagerová, A.
A1 - Lailik, O.
A1 - Miksová, R.
A1 - Poustka, D.
A1 - Mistrík, J.
A1 - Holý, V.
A1 - Schütter, Jan David
A1 - Kentsch, U.
A1 - Marvan, P.
A1 - Azarov, A.
A1 - Galeckas, A.
T1 - Combined Au/Ag nanoparticle creation in ZnO nanopillars by ion implantation for optical response modulation and photocatalysis
N2 - ZnO nanopillars were implanted with Au-400 keV and Ag-252 keV ions with ion fluences from 1 × 10^15 cm^2 to 1 × 10^16 cm^2. We compared ZnO nanopillars solely implanted with Au-ions and dually-implanted with Au and Ag-ions. Rutherford Back-Scattering spectrometry (RBS) confirmed Ag and Au embedded in ZnO nanopillar layers in a reasonable agreement with theoretical calculations. A decreasing thickness of the ZnO nanopillar layer was evidenced with the increasing ion implantation fluences. Spectroscopic Ellipsometry (SE) showed a decrease of refractive index in the nanopillar parts with embedded Au, Ag-ions. XRD discovered vertical domain size decreasing with the proceeding radiation damage accumulated in ZnO nanopillars which effect was preferably ascribed to Au-ions. SE and diffuse reflectance spectroscopy (DRS) showed optical activity of the created nanoparticles at wavelength range 500 – 600 nm and 430 – 700 nm for the Au-implanted and Au, Ag-implanted ZnO nanopillars, respectively. Photoluminescence (PL) features linked to ZnO deep level emission appear substantially enhanced due to plasmonic interaction with metal nanoparticles created by Ag, Au-implantation.
Photocatalytic activity seems to be more influenced by the nanoparticles presented in the layer rather than the surface morphology. Dual implantation with Ag, Au-ions enhanced optical activity to a larger extent without significant morphology deterioration as compared to the solely Au-ion implanted nanopillars.
KW - ZnO nanopillars
KW - Au/Ag nanoparticles,
KW - Ion implantation
KW - SPR
KW - Doped ZnO nanostructures
PY - 2022
DO - https://doi.org/10.1016/j.apsusc.2022.155556
SN - 0169-4332
VL - 610
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-56306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sergievskaya, A.
A1 - Absil, R.
A1 - Chauvin, A.
A1 - Yusenko, Kirill
A1 - Vesely, J.
A1 - Godfroid, T.
A1 - Konsstantinidis, S.
T1 - Sputtering onto liquids: How does the liquid viscosity affect the formation of nanoparticles and metal films?
N2 - This paper reports on the effect of the solvent viscosity on the formation of gold nanoparticles (Au NPs) during Sputtering onto Liquid (SoL) process. All other parameters related to the plasma and the host liquid are kept constant. SoL is a simple highly reproducible approach for preparation of colloidal dispersions of small naked NPs. The properties of the final product are determined by both the sputtering parameters and the host liquid characteristics. As a model system we chose to sputter a gold target by a direct-current magnetron discharge onto a line of polymerized rapeseed oils having similar surface tension (32.6 ― 33.1 mJ·m-2 at RT). It was found that well dispersed Au NPs grow in the bulk solution of oils with low viscosities (below 630 cP at 25 °C) while gold films form onto the surface of high viscosity liquids (more than 1000 cP at 25 °C). The mean diameter of the individual Au NPs slightly increases with oil viscosity and is in range about 2.1―2.5 nm according to transmission electron microscopy.
KW - Liquid spattering
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.1039/D2CP03038A
SN - 1463-9084
VL - 25
IS - 4
SP - 2803
EP - 2809
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-56562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Katrin
A1 - Schmitt Rahner, M.
A1 - Stolzenberg, U.
A1 - Kraft, Sebastian
A1 - Bonse, Jörn
A1 - Feist, C.
A1 - Albrecht, D.
A1 - Pullner, B.
A1 - Krüger, Jörg
T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing
N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2.
KW - Ultrashort pulsed laser
KW - X-ray emission
KW - X-ray spectrum
KW - X-ray energies
KW - Radiation protection
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176
DO - https://doi.org/10.3390/ma15248996
VL - 15
IS - 24
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-56617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Einführung Ultrakurzpulslaser
N2 - Der Vortrag gibt eine Einführung zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und dem Schutz gegenüber unerwünschter Röntgenstrahlung bei der Ultrakurzpulslaser-Materialbearbeitung.
T2 - Vorkommnisse in der Medizin und Ultrakurzpulslaser, Veranstaltungsreihe: Erfahrungsaustausch zu Themen des Vollzugs im Strahlenschutz
CY - Cologne, Germany
DA - 26.04.2023
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
KW - Abschirmung
PY - 2023
AN - OPUS4-57408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Pearce, Ben K.D.
A1 - Etter, Martin
A1 - Truong, Khai-Nghi
A1 - Ostojić, Tea
A1 - Krajnc, Andraž
A1 - Mali, Gregor
A1 - Rossi, Barbara
A1 - Molčanov, Krešimir
A1 - Lončarić, Ivor
A1 - Meštrović, Ernest
A1 - Užarević, Krunoslav
A1 - Grisanti, Luca
T1 - Base-pairing of uracil and 2,6-diaminopurine: from cocrystals to photoreactivity
N2 - We show that the non-canonical nucleobase 2,6-diaminopurine (D) spontaneously base pairs with uracil (U) in water and the solid state without the need to be attached to the ribose-phosphate backbone. Depending on the reaction conditions, D and U assemble in thermodynamically stable hydrated and anhydrated D-U base-paired cocrystals. Under UV irradiation, an aqueous solution of D-U base-pair undergoes photochemical degradation, while a pure aqueous solution of U does not. Our simulations suggest that D may trigger the U photodimerization and show that complementary base-pairing modifies the photochemical properties of nucleobases, which might have implications for prebiotic chemistry.
KW - Mechanochemistry
KW - In situ monitoring
KW - Cocrystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608622
DO - https://doi.org/10.1016/j.isci.2024.109894
VL - 27
IS - 6
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-60862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davison, Nathan
A1 - Hemingway, Jack M.
A1 - Wills, Corinne
A1 - Stolar, Tomislav
A1 - Waddell, Paul G.
A1 - Dixon, Casey M.
A1 - Barron, Luke
A1 - Dawson, James A.
A1 - Lu, Erli
T1 - Mechanochemical Synthesis of a Sodium Anion Complex [Na+(2,2,2-cryptand)Na–] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions
N2 - Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is −1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na–], which allows us to unveil a versatile reactivity profile of this once exotic species.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608632
DO - https://doi.org/10.1021/acs.inorgchem.4c02914
VL - 63
IS - 32
SP - 15247
EP - 15258
PB - American Chemical Society (ACS)
AN - OPUS4-60863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Parthasarathy, Thiyagaraj
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Ghosh, Soumyajit
T1 - Design of mechanically flexible photoresponsive cyanostilbene molecular crystals
N2 - Photoresponsive molecular crystals have sparked interest owing to their potential application prospects. In this study, we achieved dual mechanical responses of a cyanostilbene-based crystal BN. The crystal exhibited both stress-induced mechanical flexibility and light-induced photomechanical bending. Two distinct mechanical responses are related to different underlying phenomena and were not interlinked. While elasticity is attributed to criss-cross packing arrangement in the isotropic structure, photomechanical bending is attributed to the formation of heterogeneous phase distribution due to monomer to dimer cycloaddition product formation. The crystal did not demonstrate photoswitching activity. However, it exhibited thermal reversibility, highlighting reversible dimer to monomer conversion.
KW - Flexible
KW - Molecular crystals
PY - 2024
DO - https://doi.org/10.1039/D4CE00571F
VL - 26
SP - 4634
EP - 4642
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60888
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -