Analytische Chemie
Filtern
Dokumenttyp
- Vortrag (404) (entfernen)
Sprache
- Englisch (337)
- Deutsch (64)
- Spanisch (2)
- Mehrsprachig (1)
Referierte Publikation
- nein (404) (entfernen)
Schlagworte
- Nanoparticles (32)
- Synchrotron (26)
- X-ray scattering (23)
- XPS (21)
- Mikroplastik (20)
- BAMline (18)
- Mechanochemistry (18)
- DNA (17)
- Geant4 (15)
- In situ (14)
Organisationseinheit der BAM
- 6 Materialchemie (404) (entfernen)
Surface analysis is still gaining importance, as most modern technology is in essence surface and thin film technology. In microelectronics and optics but also in many fields of energy storage and conversion, thin surface layers or structured surfaces are key components. Optical surface measurements are useful because of their reliability, robustness, and scalability – properties, which are especially desirable in a production environment. However, many of these methods take require considerable effort in data analysis. Spectroscopic ellipsometry (SE) is maybe the prime example of this class of methods. To combine the advantages of SE with metrological trueness and traceability, we combine it in a group of other methods, such as electron microscopy, instrumental surface analysis, X-ray diffraction.
This presentation will give an overview on the principles of SE, its available quantities and the general properties of this measurement technique. Several examples from current and past projects of BAM-6.7 will show how a measurement community involving ellipsometry can benefit many fields of interest, from polymer science to energy applications. In the context of creating a “measurement landscape”, standardisation and standard compliance play an important role. The efforts of BAM in standardisation and accrediting of ellipsometry will be shown demonstrating the possible impact on quality assurance in different fields of technology.
Ferritic high temperature alloys are widely used as boiler tube and heat exchanger materials in coal, biomass and co-fired power plants. All technologies have in common that the applied materials are exposed to different temperatures, process pressures and reactive atmospheres that lead to a change of the material properties and a further degradation of the material. Material changes caused by aging in highly corrosive and toxic gases such as SO2 are mainly studied ex situ after the reaction is finished. The solid material is deposited in the atmosphere for a certain period of time, and material changes are then examined by various microscopic techniques such as optical microscopy (OM), electron microprobe analysis (EMPA), scanning electron microscopy (SEM and TEM) and X-ray diffraction (XRD). Nevertheless, extensive efforts were made to study material changes of high temperature alloys under oxidizing and reducing atmospheres by environmental scanning electron microscopy or in situ TEM techniques However, the possibilities of microscopic in situ techniques are very limited for the use of highly corrosive and toxic gases such as SO2. Since Sulfur induced corrosion at temperatures relevant for coal and biomass fired power plants, which is causing breakaway oxidation and sulfide precipitation at grain boundaries, is still of scientific interest, the current work focuses on the effect of SO2 in an initial stage of corrosion of ferritic alloys. For the analysis of early stages of combined oxidation and sulphidation processes of Fe-Cr model alloys the usage of a light furnace to conduct a rapid reactive annealing experiment is feasible. Previous studies presented distinct results of the influence of chromium on early high temperature corrosion by SO2 by this technique and subsequent classical metallographic analyses. However, it is still not possible to trace the corrosion mechanism in real time by conducting single aging experiments. The current work introduces two different approaches to study the initial stages of high temperature oxidation processes by applying above state of the art X-ray diffraction and spectroscopy methods. One part focuses on the real time observation of the formation of corrosion products such as oxides and sulfides by energy dispersive X-ray diffraction (EDXRD). The potential of this technique to study crystallization and growth processes of thin films in a reactive environment in real time was previously shown for different compound semiconductors. This approach was now applied to follow oxidation and sulphidation processes of ferritic model alloys in SO2 and SO2/H2O environments. The diffraction signals of the X-rays were detected during the corrosion process and the peak area and positions were analyzed as a function of time. This procedure enables monitoring external oxide growth and material loss in real time in an early stage of corrosion.
The other part of the current work presents the possibilities of X-ray absorption near edge structure spectroscopy (XANES) to characterize oxide scales and their growth mechanisms. Precise phase identification and quantification of corrosion products in a multi-phase oxide/sulfide scale is a pre-requisite to understand diffusion paths of metal ions and gas components. It is a challenging task to distinguish structurally similar reaction products such as Fe3O4 and FeCr2O4 especially in thin films with texture effects by diffraction. To illustrate for example Cr-out diffusion of an alloy throughout an inner and external oxide scale the differentiation of Fe3O4 and FeCr2O4 is indispensable. XANES uses the photoionization effect at the metal absorption edge in an aging product and accesses by this structural and chemical information. The current work uses XANES at the Fe-K and Cr-K absorption edge to identify various aging products grown as thin layers on alloys after short time aging experiments. A reaction chamber for combining high temperature oxidation experiments with surface sensitive X-ray absorption near edge structure spectroscopy will be introduced and first results of XANES on scales at high temperatures will be presented.
Ferritic-martensitic alloys with 12-16 % Cr in weight are subject to devices for various energy systems, such as coal power plants and waste incineration plants. These materials are exposed to a highly corrosive environment which lead to a degradation of the material. Especially the simultaneous oxidation and sulfidation is thereby of special interest. Proper spatially resolved measurements that determine not only chemical compositions but phases are rare. However, precise phase identification and quantification of corrosion products within the multi-phase corrosion scales is a key aspect to understand diffusion paths of metal ions and gas ions/molecules. This study investigated Fe-Cr model alloys with Cr contents from 0 to 13 % in weight in 0.5 % SO2 and 99.5 % Ar atmosphere to aim in a fundamental and systematic analysis. Samples were aged at 650 °C for time scales from 12 h to 250 h. The results presented here correspond to depth dependent phase identification of oxide and sulphide phases in the corrosion scales by using X-ray absorption near edge spectroscopy (XANES). Per sample a series of ca. 20 spots (1-5 µm spot size) from scale-gas to scale-metal interface were measured. XANES spectroscopy was performed at the Fe-K edge (7.11 keV) on polished cross sections. The collected spectra were fitted to a combination of reference materials to quantify the present phases at different positions within the scale.The phase distribution differs with Cr content and the Cr diffusion through pure Fe-oxide and mixed Fe-Cr-oxide phases is discussed.
In-Situ SAXS Techniques
(2018)
Our project's aim is to enhance the capabilities of additive manufacturing techniques, where enabling a Two-Photon-Polymerization (TPP) 3D printer of producing arrays of precisely aligned nanoparticles is of an enormous value. As heterogeneous functional nanostructures with arrays of oriented nanoparticles are very promising in many fields; electrochemistry, energy storage, nanoelectronics among other vital fields.
The feasibility and the convenience of orienting nanoparticles using magnetic, electric fields and ultrasonic vibrations will be systematically investigated, using Small Angle X-ray Scattering (SAXS), since SAXS can provide detailed information about the orientation characteristics of nano-Ensembles. Corresponding to our prerequisites, a set ad hoc functional sample holders, sample stages and other In-Situ SAXS solutions were developed, and incorporated to be compatible with a state-of-the-arts SAXS machine, called Multi-scale Analyzer for Ultrafine Structures (MAUS).
The MAUS has been customized and engineered to serve as a miniaturized synchrotron, and that is exactly what we need.
Experiments attempting to orient superparamagnetic nanoparticles will be discussed, where the outcomes will not only help in understanding the mechanics of field-particle interactions, it will also help in further developing the adequate needed set of corrections to the SAXS data, that is especially regards oriented samples.
The CLEAN ENERGY Flagship is an initiative designed to utilize recent game changing developments in digital, materials and manufacturing technologies to catalyze a radical paradigm shift towards clean, reliable, efficient and cost-optimal energy.
Unifying and drastically accelerating radically new energy material design, processing and integration across the entire value chain addressing energy production, conversion, storage and systems.
CLEAN ENERGY participants are all distinguished research organisations that each benefit from their own industry networks and contacts with regions and state-level activities and have a long history of collaborating with each other (for 10 years now under the umbrella of EERA) within a European collaborative framework.
Through EERA, CLEAN ENERGY aims to become a crucial partner in the SET-Plan, supporting long-lasting approaches through its established networks and internal collaborations.
The development of quick and simple optical sensing technologies for Endocrine Disrupting Chemicals (EDCs) is needed to facilitate monitoring of these substances to ensure consumer safety. Optical sensing was achieved against phthalates acting as EDC that have host guest interaction with an intercalated Metal-organic framework (MOF), resulting in a fluorescence emission upon excitation. The fluorescent turn-on signal was generated by using a fluorophore with a structural component that has little fluorescence unless excimers are formed. Strategies to engineer functional MOF structures suitable for sensing EDC phthalates were developed, and the characterization of the MOFs with and without present phthalates was done by single crystal XRD, PXRD, RAMAN and Thermogravimetry. Extensive photo-physical characterization of host-guest complexes of different phthalates and the MOF as well as the resulting exciplex fluorescence was performed. Photo physical characterization revealed an analyte specific fluorescence fingerprint that allows discerning even minute changes in chemical structures of the analyte and therefore paving the way for sensing tools in real world analytical applications. The presented capability of MOFs to sense EDCs is envisioned to complement established methods from analytical chemistry such as mass spectrometry based methods which can’t be used on site and are often associated with infrastructural capacity constraints
Quantifizierung der Schädigung von DNA in wässriger Lösung unter direkter Elektronenbestrahlung
(2018)
To cure cancer radiation therapy is used to kill tumor cells.
It is based on radiation induced damage to biomolecules.
Especially DNA damage is of key interest due to its central role in apoptosis and mutation.
Because of the high amount of water in biological tissue, most of the damage is caused by the secondary particles produced by the inelastic scattering of ionizing radiation and water.
A detailed understanding of the underlying molecular processes under physiological conditions is the prerequisite to develop more efficient therapies.
Goal of this work is to quantify the DNA damage caused by ionizing radiation in dependence of the inelastic scattering events and the energy deposit within the microscopic target volume of biological relevance.
The irradiations have to be performed in liquid, under consideration of the chemical environment.
Therefore, a new combination of experiment and Monte-Carlo simulations was developed and tested.
To make it possible to irradiate liquids with electrons within scanning electron microscopes a new sample holder was constructed incorporating an electron transparent nanomembrane.
It makes it possible to irradiate DNA, proteins or cells at different pH, salinity and in the presence of cosolutes.
%The most important results of this work are as follows:
The median lethal dose for a model system of plasmid DNA and water was determined by the combination of experimental data, particle scattering simulations (Geant4-DNA) and diffusion calculations as D0.5=(1.7+-0.3) Gy.
From the convolution of plasmid positions and the spatially resolved energy deposit, as determined by electron scattering simulations, the histogram of the energy deposit within the target volume of the plasmids and the microscopic median lethal energy deposit was calculated as E0.5=6+-4eV.
It could be deduced that on average less than two ionization events are sufficient to cause a single-strand-break.
The relation of single-strand-breaks (SSB) to double-strand-breaks (DSB), which is of importance for microdosimetric modeling, was determined as SSB:DSB = 12:1.
The presented method for the determination of microscopic dose-damage relations was further extended to be applicable for general irradiation experiments.
It becomes independent of the type of primary radiation used, the experimental geometry, and the diffusional properties of the molecules under investigation.
This way different experimental systems with varying, inhomogeneous energy deposit characteristics become comparable with each other, which is not possible when only macroscopic averaged values are taken into account.
In addition, the radiation protection properties of the compatible solute ectoine, as well as its influence on the water properties and biomolecules were investigated.
%In addition, the influence of the compatible solute ectoine on water, biomolecules and its radiation protection properties were investigated.
Raman spectroscopy revealed a concentration dependent increase of the collective water modes in the OH-stretching region, which was found to be independent of the sodium chloride concentration.
Molecular dynamic simulations showed that the zwitterionic properties of ectoine lead to its half-chair conformation.
The hydrogen bonds in the first hydration shell are more stable and have an increased lifetime compared to the bulk water.
Irradiation experiments with DNA in the presence of 1M ectoine revealed an increase of the survival rate by a factor of 1.41 as compared to the absence of ectoine.
The protective properties of ectoine result from the increase of the inelastic scattering probabilities of low energy electrons at the acoustic vibrational modes of water and its properties as OH-radical scavenger.
This was shown by Raman spectroscopy and electron paramagnetic resonance measurements (EPR).
Photoelectron spectroscopy
(2018)
Analytical Sciences has developed from Ostwald’s “unentbehrlichen Dienstmagd” to a chemical discipline at the core of many of today’s fundamental and applied scientific problems and innovations. An atomic or molecular understanding of basic processes in chemistry, soft matter physics, materials and life science is enabled only through new analytical methods and instrumentation. Similar observations can be found for pressing sociopolitical conflicts of the future: A rational discussion of global climate change or new energy sources is only possible with reliable analytical results. Progress in Analytical Sciences is only possible if the underlying interdisciplinary character is acknowledged and valued. The talk will illustrate the scope of modern Analytical Science through examples from process analysis relevant to modern process intensification and industry 4.0 to bioanalysis and the use of synchrotron radiation to elucidate fundamental reactions materials.
The state of fresh concrete is predominantly determined by the rheological properties of the cement paste. In order to control performance spectra and requirements of novel concretes and to better understand macroscopic phenomena, comprehensive knowledge of the material behavior of fresh cement suspensions as well as of the complex relationships of mechanisms at the nano and micro scale are necessary. This work focuses on micro and nano rheology of suspensions of cementitious model systems and the influence of polycarboxylate-based admixtures on the rheology. The phenomena are driven by multiple parameters such as adsorption and particle interactions. Hence, the first part examines the interaction between polycarboxylate ether (PCE) and synthesized clinker phases and hydration products as model systems with regard to early hydration products.
Nowadays, different nanoparticles have been developed for commercial applications. However, since data on toxicity are barely available, their increasing application in cosmetic products, food and their release in the environment might cause severe problems. An accurate separation, identification and characterization of nanoparticles becomes increasingly important1,2.
In this presentation, a two-dimensional separation approach based on AF4 and CE was showed and used to separate NPs with similar sizes but different coatings. Standard reference polystyrene NPs having comparable core sizes but different coatings were investigated. Different migration time and profiles were compared. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots in case of 20 and 50 nm particle mixtures, whereas the 100 nm NP mixture could not be separated. Various factors affecting the separation like hydrodynamic diameter or SDS concentration were discussed.
Future investigations will be focussed on inorganic NPs with differently charged coatings. There, AF4-CE coupling can be coupled with inductively coupled plasma mass spectrometry (ICP-MS) to enhance the sensitivity of this method.
Nowadays, different nanoparticles have been developed for commercial applications. However, since data on toxicity are barely available, their increasing application in cosmetic products, food and their release in the environment might cause severe problems. An accurate separation, identification and characterization of nanoparticles becomes increasingly important.
A common method for nanoparticle separation, which was introduced in 1976 by Giddings, represents asymmetrical field-flow fractionation (AF4). It is a flow based separation method, which can be theoretically used to separate particles range from 1 nm to 50 µm. However, when the particles are smaller than 10 nm, separation with AF4 will become difficult to perform. Because in this case strong separation force, which induces aggregation of particles, should be applied. This will decrease recoveries of analytes and limit its application in accurate quantitative analysis. Capillary electrophoresis (CE) is another well-developed separation technique, in which samples will be separated in relation to their electrophoretic mobility. In recent years, CE has been used to separate different kinds of nanoparticles like, gold colloids or CdSe Quantum dots. However, till now only separation of particles smaller than 50 nm was reported. Because large size distribution of bigger particles will result in strong peak broadening and long separation time.
A two-dimensional coupling of AF4 and CE might provide us a new separation method, which can extend the separation ranges of both methods and be a way to characterise particles with large size distributions.
Nowadays, different nanoparticles have been developed for commercial applications. However, since data on toxicity are barely available, their increasing application in cosmetic products, food and their release in the environment might cause severe problems. An accurate separation, identification and characterization of nanoparticles becomes increasingly important.
A common method for nanoparticle separation, which was introduced in 1976 by Giddings, represents asymmetrical field-flow fractionation (AF4). It is a flow based separation method, which can be theoretically used to separate particles range from 1 nm to 50 µm. However, when the particles are smaller than 10 nm, separation with AF4 will become difficult to perform. Because in this case strong separation force, which induces aggregation of particles, should be applied. This will decrease recoveries of analytes and limit its application in accurate quantitative analysis. Capillary electrophoresis (CE) is another well-developed separation technique, in which samples will be separated in relation to their electrophoretic mobility. In recent years, CE has been used to separate different kinds of nanoparticles like, gold colloids or CdSe Quantum dots. However, till now only separation of particles smaller than 50 nm was reported. Because large size distribution of bigger particles will result in strong peak broadening and long separation time.
A two-dimensional coupling of AF4 and CE might provide us a new separation method, which can extend the separation ranges of both methods and be a way to characterise particles with large size distributions.
Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist eine Ressortforschungseinrichtung, die zum Schutz von Mensch, Umwelt und Sachgüter, forscht, prüft und berät. Im Fokus aller Tätigkeiten in der Materialwissenschaft, der Werkstofftechnik und der Chemie steht dabei die technische Sicherheit von Produkten und Prozessen. Dazu werden Substanzen, Werkstoffe, Bauteile, Komponenten und Anlagen sowie natürliche und technische Systeme erforscht und auf sicheren Umgang oder Betrieb geprüft und bewertet. Schwerpunkt des Vortrages sind multimodale Polymeranalytik, nanoskalige Sensormaterialien und die Charakterisierung von technischen Eigenschaften von Polymeren sowie ihre Alterung und Umweltrelevanz.
Solution doping of off-the-shelf plastic optical fibers (POFs) represents rather simple and cheap way for preparing custom cladding-doped POFs (CD-POFs) with short to medium lengths. CD-POFs are especially attractive for environmental sensing applications, but might be of interest for illumination task as well. In this work, the proposed doping technique is tested with three different commercial low-cost polymethyl methacrylate (PMMA) POFs; Eska CK-40 and Eska GK-40 from Mitsubishi Rayon and Raytela PGU-FB1000 from Toray. The aim of the work is to aid the selection of the most suitable fiber yielding highest optical quality of prepared CD-POFs. Firstly, the optimal doping times are determined for the individual fiber types using short fiber samples. Secondly, longer 10 m CD-POFs are prepared from all tested fibers using the optimized doping procedure. Finally, attenuation of pristine POFs and prepared CD-POFs is measured using optical time domain reflectometry in order to characterize the impacts of the doping on fiber optical properties. In addition, the importance of post-doping drying procedure for CD-POF optical performance is investigated as well. The results suggest that, although doping of all tested fibers is generally feasible, Eska CK-40 is the most suitable candidate with regard to the doping efficiency and fiber post-doping performance.
The damage caused by ionizing radiation to DNA and proteins is the reason to treat cancer by radiation therapy. A better understanding of the molecular processes and quantification of the different damaging mechanisms is the prerequisite to develop more efficient therapies. Hereby the understanding of the processes involved in the damage to DNA are of key interest due to its central role in reproduction and mutation.
For radiation with low linear energy transfer (LET), most of the damage is caused by the secondary particles produced by scattering of the ionizing radiation with water. Thereby a multitude of species are produced, whereby especially kinetic low energy electrons, prehydrated electrons, OH-radicals and ions are of importance. With higher LET the relative amount of the direct damaging effects increases. This is especially important considering the increased usage of high LET nucleons in radiation therapy. Therefore, the quantification of the contribution to DNA damage of direct and indirect effects and the different secondary species is of high interest due to the increase of radio biological efficiency when applying high LET radiation.
Here we present an approach to investigate the relative contributions to DNA strand break yield for radiation of different LET within a single electron microscope in combination with electron scattering simulations.
Universität Berlin Radiation damage to biomolecules such as DNA, is the reason to treat cancer via radiation therapy. The understanding of the molecular processes and the quantification of the underlying damaging mechanisms is necessary to develope more efficient irradiation protocols for cancer therapy. Thereby damage to DNA is of key interest due to its central role in reproduction and mutation. Due to the high amount of water in biological tissue, most of the damage is caused by the secondary particles which are produced by the interaction of ionizing radiation with water. Thereby a multitude of species are produced, e.g. kinetic low energy electrons, prehydrated electrons, OH-radicals and ions. The quantification of the contribution to DNA damage by the various species is of interest. Here we present an experimental approach to disentangle their relative DNA strand break yields. Plasmid DNA (pUC19 ) is irradiated in water with electrons under the presence of different scavengers. The presented preliminary results reveal the relative contributions of OH-radicals, low energy electrons and prehydrated electrons and their DNA single and double strand break yields.
Mechanochemistry is increasingly used for synthesizing soft matter materials including metal organic compounds and cocrystals. The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Time-resolved in situ investigations of milling reactions provide direct insights in the underlying mechanisms. We introduced a setup enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy. The specific combination allows to study milling processes comprehensively on the level of the molecular and crystalline structure and thus obtaining reliable data for mechanistic studies. We discuss our recent results investigating the formation of (polymorphic) cocrystals. First investigations of a mechanochemical synthesis under controlled temperature which allow determining the activation barrier are presented.6 Furthermore, X-ray diffraction and in situ Raman spectroscopy coupled with thermography revealed a low temperature increase during milling reactions due to the mechanical impact and clear temperature increases as a result of the reaction heat. Our results indicate that in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemically synthesized compounds.
Some critical discussion of the state of the art of uncertainty evaluationin Instrumented Indentation Testing IIT
Nowadays the Instrumented Indentation Testing (IIT), in the nano range often named as nano indention, is one of the most commonly used methods to determine the mechanical properties of materials in the micro and nano range. This method is already extensive standardized in ISO 14577 part 1-4. In the past, the application of this standard in testing praxis shows that the established values have an excellent precision.If an uncertainty is calculated, the range of values within which the true value is asserted to lie with some level of confidencewill be known. In part 1 of ISO 14577 [1] two methods for evaluation of the uncertainty in IIT are mentioned:
Method 1 for determining uncertainty considers only those uncertainties associated with the overall measurement performance of the testing machine with respect to the reference blocks.
Method 2calculates a combined uncertainty from individual contributions. These may be grouped into random and systematic uncertainties.
Both methods will be described in detail using examples from the dailyexperimental praxis. The comparabilityof both methods will be critically discussed. Finally, it will be showedhow the calculated uncertaintiescan be used for performancetests and product specifications.
Acknowledgement
This work was performed under the support of the EMPIR project 17NRM05Advancing measurement uncertainty̶ comprehensiveexamples for key international standards
References
[1] ISO 14577 part 1 (2017)
Measurement of elemental composition of Fe1-xNix and Si1-xGex alloy thin films by EMPA and µ-XRF
(2019)
It was demonstrated in the past that the electron probe microanalysis (EPMA) can be applied to determine accurately both elemental composition and thickness of thin films by using the dedicated software package for thin film analysis Stratagem. A relatively small number of film materials such as pure metallic films of platinum and nickel, binary alloys of Fe-Ni, and Pt-Ni-Co ternary alloy films has been reported in literature as working successfully. Further, the software can be applied ‘inversely’, i.e., by feeding it with the thickness of the film and using the determined mass coating, one can easily calculate the film density, which for porous layers leads us to the true film porosity.
The present study repeats measurements on an already tested system of Fe-Ni thin films on silicon and reports for the first-time results of analysis on Si-Ge thin films deposited on a non-conductive aluminium oxide substrate. Standard-based and standardless EPMA (with EDS) results were used in combination with Stratagem for the quantification.
Further, X-ray fluorescence analysis (XRF) can be used for the determination of elemental composition and thickness of such films as well. In this case, XRF with a μ-focus X-ray source (μ-XRF) attached to a SEM was applied. For quantification, a fundamental parameter (FP) approach has been used to calculate standard-based and standardless results. Compared to EPMA, XRF has a larger information depth and a higher elemental sensitivity because of a generally lower background.
Both thin film systems have been chosen as samples of an international round robin test (RRT) organised in the frame of standardisation technical committee ISO/TC 201 ‘Surface chemical analysis’, under the lead of KRISS. The main objective of the RRT is to compare the results of atomic fractions of Fe1-xNix and Si1-xGex alloy films obtained by different surface Analysis techniques, such as X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) applied in the depth-profiling operation mode.
Five samples of different atomic fractions of each thin film system, i.e., Fe1-xNix and Si1-xGex, have been grown by ion beam sputter deposition on silicon and Al2O3 wafers, respectively. Reference FeNi and SiGe films with well-known elemental composition and thickness have been also supplied for standard-based analysis. The atomic fractions of all the samples including the references have been certified by RBS (Rutherford backscattering spectrometry) and ICP-AES (inductively coupled plasma atomic emission spectroscopy).
The 44th Meeting of the Versailles Project on Advanced Materials and Standards (VAMAS) Steering Committee has just taken place at NIST in Boulder (CO, USA). BAM participates with significant contributions in Technical Working Areas on nanoparticle and surface chemistry characterization, but also has positioned itself to new global material challenges and trends in the developement of advanced materials and their characterization, such as thermal properties, self-healing materials, and micro- and nanoplastic.
Everything SAXS
(2019)
Experimenting on MAUS
(2019)
Metal-organic frameworks (MOFs) are suitable materials for gas storage of small molecules due to their nanoporous, crystalline structure. The extensively studied MOF HKUST-1 consist of Cu(II)-dimers in a paddlewheel structure, with 1,3,5-benzenetricarboxylic acid (BTC) as organic linker. Instability to humidity remains an issue for many types of MOFs, and for HKUST-1, it has been found that exposure to water vapor creates a surface barrier which reduces the gas uptake rate.
Near-ambient pressure XPS (NAP-XPS) is a promising method for investigations of the stability and interaction of HKUST-1 with various gas molecules. The oxidation state of copper can be monitored before, during and after exposure to various gases. This does not only provide information on the stability of the MOFs, but also on the interaction with the gas molecules and the reversibility of the processes.
NAP-XPS measurements of HKUST-1 exposed to methanol, pyridine and water vapor were performed with EnviroESCA, a laboratory NAP-XPS instrument developed by SPECS. Cu 2p, O 1s and C 1s core level spectra were acquired in pressure ranging from 10-5 to 8 mbar to assess the oxidation state of copper and the stability of the organic linker. HKUST-1 does not show interaction with pyridine, but there are indications of copper-reduction upon exposure to methanol and water vapor. Radiation induced damage is considered and two different approaches for determining the ratio of Cu(I) to Cu(II) will be discussed.
It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available.
The challenge consists in a clever combination of these techniques coordinated with the heterogeneity to be investigated.
A number of applications will be presented from e.g. topology elucidation of branched EO-PO “academic” copolymers to copolymer composition of partially broadly distributed progressively tailored “industrial relevant” copolymers consisting of e.g. polyamides, polycarbonates and polysiloxanes.
Multidimensional separation techniques will be demonstrated with focus on mass spectrometric detection techniques (ESI-/MALDI-TOF-MS) coupled online or semi-online to prior separation.
Der Vortrag beschreibt den Entwicklungsprozess des Analysenverfahrens TED-GC-MS zur Bestimmung von Mikroplastikgehalten in Umweltproben im Rahmen des BMBF-Projektes MiWa. Die Funktionsweise, die Automatisierung und die Optimierung einzelner Geräteparameter und Leistungsdaten werden gezeigt. Untersuchungen des Einflusses von Probenmatrices werden dargestellt und die Ergebnisse einiger Messkampagnen und Ringversuche vorgestellt, die die Routinefähigkeit des Verfahrens dokumentieren.
Perhaps due in no small part to its historical mystique, mechanochemistry has been shrowded in relative obscurity for quite some time. The successes of mechanochemistry in organic synthesis have often been curtailed by a fundamentally limited mechanistic understanding. Lately, however, the community has made great strides towards understanding the fundamentals, as well as large steps forward regarding industrially significant scale-up via twin-screw extrusion. A variety of recent work has traded in some of mechanochemistry’s mystique for simple, straight-forward chemical guidelines.
The test material EDS-TM001 together with an accompanying software package, “EDS spectrometer check”, have been made available in 2009 by BAM to be employed by EDS (energy-dispersive X-ray spectrometer) users to check the performance of an EDS with a SEM. With EDS-TM001/002 test material, this periodical check is simplified to the acquisition of only one 10 kV spectrum. The software “EDS spectrometer check” is destined to evaluate automatically this spectrum and determine the EDS performance in terms of energy resolution and calibration, as well as possible alteration of low-energy efficiency due to detector contamination. Energy resolution can be compared with the specified values according to the international ISO standard ISO 15632:2012.
EDS-TM is a synthetic material consisting of a 6 μm thick layer of C, Al, Mn, Cu and Zr deposited on a steel (EDS-TM001) or silicon (EDS-TM002) substrate. The chemical composition of EDS-TM was chosen such as to give nearly equal intensities of the low energy lines in a 10 kV spectrum, thus, making it very sensitive against spectrometer efficiency changes. New results and gained experiences will be presented.
When the FWHM of the X-ray lines in the EDS-TM spectrum are determined, the spectrum Background must be subtracted accurately. The applied physical background subtraction procedure is robust and considers the transmission of the detector window. While the previous version considers only Moxtek AP windows, the new software version includes selection of silicon nitride window and the case of windowless detector.
Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of thin porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the homogenous dispersion of the active species within the porous matrix. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by complementary analysis of SEM/EDS, ToF-SIMS, NanoSIMS, AES and spectroscopic ellipsometry.
Mesoporous iridium oxide - titanium oxide (IrOx-TiOx) films can be prepared by a well-established Synthesis route via soft-templating. IrOx-TiOx films are very sensitive to the conditions of synthesis. Analysis by SEM and NanoSIMS imaging suggests IrOx-TiOx films with and without a homogenous dispersion of IrOx within the TiOx film matrix under different synthesis conditions.
Auger electron spectroscopy (AES) analysis in the depth-profile mode as well as cross-section line-scan AES measurements of an inhomogeneous IrOx-TiOx film indicate the presence of an IrOx-rich Phase dispersion both at the surface of IrOx-TiOx film as well as within the film.
The contribution will assess in detail the sensitivity of the synthesis conditions and the characterization of the thin metal oxide films. Moreover, the correlation between and comparison to other measurement techniques will be discussed.
New reference material candidates for traceable size measurement of nonspherical nanoparticles
(2019)
Size measurement of nanoparticles (NP) becomes a challenging analytical problem when non-spherical shapes must be traceably measured. However, most industrial NPs have irregular shapes and broad size distribution making it often more complex to follow European regulatory to identify a material as a nanomaterial according to which accurate measurement of the smallest dimension and its size Distribution is necessary.
The European research project nPSize - Improved traceability chain of nanoparticle size measurements aims to fill this gap by developing potential non-spherical reference nanoparticles, measurement procedures and physical modelling to improve the traceability chain, comparability and compatibility for NP size measurements between different methods. Therefore, new model NP with well-controlled shape has been synthesized and are supposed to be systematically characterized using the traceable methods scanning/transmission electron microscopy, atomic force microscopy and small angle X-ray scattering.
Following NP candidates are under investigation with respect to their homogeneity and stability: (i) titania nanoplatelets (10-15 nm thickness x 50-100 nm lateral), (ii) titania bipyramides (~60 nm length x 40 nm width), (iii) titania acicular particles (100 nm length x 15-20 nm width; aspect ratio 5.5/6), (iv) gold nanorods (~10 nm width x 30 nm length), and (v) gold nanocubes (~55 nm x 55 nm x 55 nm). In addition, sample preparation procedures as well as measurement analysis procedures with evaluation of appropriate measurands and descriptors for each material class and method are being developed to support standardization. To underpin the traceability of the size measurement of nonspherical NP, physical modelling of the signals in e.g. electron microscopy techniques will be used and in combination, the implementation of machine learning is aimed to facilitate measurement Analysis procedures, especially regarding the accurate thresholding/segmentation of the NPs.
Die zunehmenden Nachweise von Kunststoffen in verschiedenen Umweltmedien erfahren in den letzten Jahren weltweit ein zunehmendes wissenschaftliches, gesellschaftliches und politisches Interesse. Besondere Aufmerksamkeit erfahren Kunststoffpartikel von 1-1.000 µm, sogenanntes Mikroplastik. Es wurde mittlerweile in Wasser, Böden, Luft und Biota nachgewiesen. Obwohl die Wirkungen auf die natürlichen Umweltfunktionen noch unklar sind und kontrovers diskutiert werden, ist allein durch die ubiquitäre Präsenz eine systematische Erfassung von Eintragsquellen und Verbleib der Partikel über alle Umweltmedien notwendig, um Maßnahmen zur Reduktion der Einträge zu veranlassen.
Für eine zuverlässige Erfassung sind medienübergreifende Verfahren zu entwickeln, welche die drei analytischen Schritte, Probennahme, Probenaufbereitung und Detektion beinhalten. Die Verfahren adressieren unterschiedliche Zielgruppen, welche verschiedene analytische Informationen fordern. Für die akademische Bewertung werden Verfahren mit hohem analytischen Aufwand favorisiert, welche möglichst detaillierte Information über Partikelsorte, -größe, -zahl und -oberflächenbeschaffenheit geben. Im Gegensatz dazu, fordern Anwender aus der Praxis schnelle und einfache Monitoring Verfahren, welche die Bestimmung eines Massengehaltes, bzw. eines Grenzwertes zulassen. Allen ist gemeinsam, dass ein hoher interdisziplinärer Anspruch besteht, der sowohl technische Voraussetzungen zur repräsentativen Probennahme und die Limitationen von Detektionsverfahren berücksichtigt, als auch die Fachkompetenz von Biologen, Umweltwissenschaften, Analytiker und Polymerwissenschaftler einschließt.
Verfahren zum Mikroplastiknachweis müssen auch verschieden Proben mit sehr unterschiedlichen Gehalten an natürlicher Matrix gerecht werden. So müssen allein für Wasser Verfahren entwickelt werden, die Mikroplastik verschiedener Form (sphärische Partikel, komplexe Bruchstücke, Fasern) aus Medien mit sehr variablen Partikelanteil (u.a. Trinkwasser, Oberflächenwasser, Abwasser) repräsentativ erfassen, sowie schnell und kostengünstig sind – einschließlich der notwendigen Probenaufbereitung. Die jeweiligen Detektionsverfahren müssen z.B. einzelne Partikel oder integrale Gehalte über drei Dekadenklassen für thermoplastische und insbesondere auch elastomere Partikelsorten erfassen können.
Bacterial samples are typically freeze dried or cryo-prepared prior to XPS analysis to allow for measurements in ultra-high vacuum (UHV). The sample environment in the near-ambient pressure (NAP) XPS instrument EnviroESCA allows for measurements in up to 15 mbar water vapor, thus, sample preparation is no longer restricted to UHV-compatible techniques. For instance, biofilms grown in medium can be transferred directly from the medium to the measurements chamber, maintaining a humid environment throughout the measurements. Considering the complexity of bacterial samples, sample preparation must be carefully considered in order to obtain meaningful and reproducible results.
In this talk, various strategies for sample preparation of bacteria and biofilms for NAP-XPS measurements will be discussed. Model systems of planktonic bacteria, artificial biofilms resembling the exopolysaccharide matrix and biofilms have been characterised in various conditions. The stability and homogeneity of the samples was assessed by monitoring the C1s core level peak at different sample locations. The quality of the XPS-spectra is also influenced by the gas environment, which will be exemplified by core level spectra of P. Fluorescens acquired in air, water vapor and ultra-high vacuum.
Metal-organic frameworks (MOFs) are suitable materials for gas storage of small molecules due to their nanoporous, crystalline structure. The extensively studied MOF HKUST-1 consist of Cu(II)-dimers in a paddlewheel structure, with 1,3,5-benzenetricarboxylic acid (BTC) as organic linker. Instability to humidity remains an issue for many types of MOFs, and for HKUST-1, it has been found that exposure to water vapor creates a surface barrier which reduces the gas uptake rate.
Near-ambient pressure XPS (NAP-XPS) is a promising method for investigations of the stability and interaction of HKUST-1 with various gas molecules. The oxidation state of copper can be monitored before, during and after exposure to various gases. This does not only provide information on the stability of the MOFs, but also on the interaction with the gas molecules.
NAP-XPS measurements of HKUST-1 exposed to methanol, pyridine and water vapor were performed with EnviroESCA, a laboratory NAP-XPS instrument developed by SPECS. Cu 2p, O 1s and C 1s core level spectra and Cu LMM Auger spectra were acquired at pressures ranging from high vacuum to 4 mbar to assess the oxidation state of copper and the stability of the organic linker. Reference measurements in argon atmosphere were conducted in order to have reference spectra with similar full width of half maxima (FHWM) as the spectra measured in reactive atmospheres. Peak fit analysis of the Cu 2p3/2 core level spectra shows that, as expected, the photoelectron signal mainly originates from Cu(II) species. The contribution from Cu(I) is negligible for samples exposed to argon and methanol, but approximately 4% for samples exposed to water vapor and 8% for samples exposed to pyridine. Within the error of the peak fit analysis, there are no changes in relative Cu(II) percentage with increasing water, methanol or pyridine exposure time pointing to saturation reached already at the lowest time of exposure.
Mechanische, topometrische und optische Charakterisierung von Schichten mit Stand der Normung
(2019)
Der Vortrag „MECHANISCHE, TOPOMETRISCHE UND OPTISCHE CHARAKTERISIERUNG VON SCHICHTEN MIT STAND DER NORMUNG“ widmet sich unterschiedlichen Beschichtungssystemen und deren mechanischer, topometrischer und optischer Charakterisierung. Über die entsprechenden aktuellen Normen wird informiert. Es betrifft Verfahren wie die Instrumentierte Eindringprüfung (IIT), Centrifugal Adhesion Testing, Weißlichtinterferenzmikroskopie, Tastschnittverfahren und Ellipsometrie (SE).
The cleaning of black carbon covered Italian marble and limestone sculptures is a challenging task for restorers and scientists, especially when black soot is penetrated into the porous surface of a stone.
Numerous sculptures of the Bode-Museum underwent two domestic fires at the repository in Berlin in May 1945, where soot damaged the surface of these artworks. Promising results in removing black layers were achieved by the application of modified gels to artificially weathered and sooted Carrara marble mockups. However, transferring the cleaning method to original samples requires a cautious proceeding with respect to short-term and long-term implications. To understand physico-chemical reactions, the analytics of gel-treated marble surfaces is of essential importance.
Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) and Auger electron spectroscopy (AES) were used to gain insights into surface chemistry and the distribution of chemical groups or fragments and enable a deeper understanding of the functionality of the applied gels and of the efficiency of tested cleaning processes. Depth profiling by ToF-SIMS is introduced as a tool to study the penetration behavior of applied cleaning chemicals.
The contribution presents the analytical methods, their possibilities and challenges, and summarizes initial results of this study.
New reference material candidates for traceable size measurement of non-spherical nanoparticles
(2019)
New model nanoparticles with well-controlled shape were synthesized within the EMPIR project nPSize - Improved traceability chain of nanoparticle size measurements. Their systematic characterization takes place by the traceable methods scanning/transmission electron microscopy, atomic force microscopy and small angle X-ray scattering. Following reference nanoparticle candidates are under investigation with respect to their homogeneity and stability: titania nanoplatelets (10-15 nm x 50-100 nm), titania bipyramides (~60 nm x 40 nm), titania acicular particles (100 nm x 15-20 nm; aspect ratio 5.5/6), gold nanorods (~10 nm x 30 nm), and gold nanocubes (~55 nm x 55 nm x 55 nm).
In well-annealed thin polymer films, with non-repulsive polymer/substrate interactions, an irreversibly adsorbed layer is expected to from. These adsorbed layers have shown greate potential for technological applications. However, their growth kinetics and molecular dynamics are still not fully understood. This is partly due to the hard accessibility of these layers in thin films. Here, the irreversibly adsorbed layers of homopolymer thin films are revealed by solvent-leaching experiments. First, the growth kinetics of these layers is investigated as a function of annealing time, annealing temperature, leaching time and the original filme thickness. The film thickness, topography and the quality of the adsorbed layer is controlled by Atomic Force Microscopy (AFM). Secondly, the molecular mobility of the adsorbed layer is investigated by Broadband Dielectric Spectroscopy (BDS). A recently developed nanostructured capacitor arrangement is employed to measure the layer with a free surface. The results are quantitatively compared and discussed with respect to recently published work.
Challenges in Traceable Size Measurement of Non-Spherical, Non-Monodisperse Nanoparticles - nPSize
(2019)
Size measurement of nanoparticles (NP) becomes a challenging analytical problem when non-spherical shapes must be traceably measured. However, most industrial NPs have irregular shapes and broad size distribution making it often more complex to follow European regulatory to identify a material as a nanomaterial according to which accurate measurement of the smallest dimension and its size Distribution is necessary.
The European research project nPSize - Improved traceability chain of nanoparticle size measurements aims to fill this gap by developing potential non-spherical reference nanoparticles, measurement procedures and physical modelling to improve the traceability chain, comparability and compatibility for NP size measurements between different methods. Therefore, new model NP with well-controlled shape has been synthesized and are supposed to be systematically characterized using the traceable methods scanning/transmission electron microscopy, atomic force microscopy and small angle X-ray scattering.
Following NP candidates are under investigation with respect to their homogeneity and stability: (i) titania nanoplatelets (10-15 nm thickness x 50-100 nm lateral), (ii) titania bipyramides (~60 nm length x 40 nm width), (iii) titania acicular particles (100 nm length x 15-20 nm width; aspect ratio 5.5/6), (iv) gold nanorods (~10 nm width x 30 nm length), and (v) gold nanocubes (~55 nm x 55 nm x 55 nm). In addition, sample preparation procedures as well as measurement analysis procedures with evaluation of appropriate measurands and descriptors for each material class and method are being developed to support standardization. To underpin the traceability of the size measurement of nonspherical NP, physical modelling of the signals in e.g. electron microscopy techniques will be used and in combination, the implementation of machine learning is aimed to facilitate measurement Analysis procedures, especially regarding the accurate thresholding/segmentation of the NPs.zeige mehr
Das Fügeverfahren Kleben bietet viele Vorteile, wie z.B. das Verbinden unterschiedlicher Materialklassen, geringe thermische Belastung (und damit ggf. verbundene Strukturveränderung/-schwächung) der Fügeteile und eine Lastverteilung über den gesamten Fügebereich. Die Auswahl an verfügbaren Klebstoffen und Vorbehandlungsoptionen sind dabei - wie die Applikationen auch - vielfältig. Es werden vier Applikationsbeispiele zu Referenzklebverbunden aus Edelstahl, zur Plasmaaktivierung von Niedrigenergie-Polymeren, zur Bestimmung der Haftfestigkeit von Lackierungen auf GFK und zur Wirkung von Primern vorgestellt. Einige Polymere weisen z.B. Eigenschaften auf, die eine Herstellung von festen und dauerhaft beanspruchbaren Kleb-verbindungen erschweren. Im Allgemeinen geht dies mit geringen Oberflächenenergien einher. Mittels Oberflächenvorbehandlung, z.B. durch Plasmafeinreinigung bzw. Plasmaaktivierung, können die Grenzflächen solcher Polymere - bezogen auf die Eignung als Fügeteile (Klebfestigkeit) oder als Substrat (Haftfestigkeit) – optimiert bzw. die Oberflächenenergie erhöht werden. Schnelle, zuverlässige und statistisch abgesicherte Prüfverfahren zur Ermittlung von Verbund-eigenschaften sind dabei unverzichtbar.
The presentation summarizes our recent results on the coupled electrochemical methods for high resolution corrosion studies. The combination of Scanning Electrochemical Microscopy (SECM) and multielectrode (MMA) based real-time corrosion monitoring was presented as a new method for achieving high time resolution in local electrochemical analysis. Correlative imaging by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) was demonstrated as a tool for the investigation of local corrosion processes initiated by the intermetallic particles (IMPs) on AA2024-T3 aluminium alloy.
The performance of functional coatings and adhesively joined hybrid components relies strongly on the stability of the polymer-metal interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to interface degradation and to develop novel strategies to increase corrosion and delamination resistance.
The aim of this project is to develop thin epoxy-based films and their carbon nanofiller loaded composites on aluminium alloy AA2024-T3 as a model system and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Spin coating was used for the layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Atomic force microscopy (AFM) results indicate a very homogeneous and dense film with low surface roughness. Carbon nanofillers were introduced either by mixing into the coating components or in between individual layers to control the separation between the carbon nanofillers and alloy surface. The film chemistry and barrier properties were characterized by means of spectroscopic and electrochemical methods, respectively. The degradation and delamination behavior of the epoxy-based films was characterized by means of in situ AFM corrosion experiments. The quantitative imaging (QI) mode allowed the observation of hydrogen-generation induced blister formation during exposure to corrosive electrolyte and how the local corrosion processes evolved with exposure time. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was performed to correlate the corrosion behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of interface chemistry and carbon nanofiller – alloy separation on the initiation of local corrosion processes on thin film covered AA2024-T3 aluminium alloys.
A selected series of dipole functionalized triphenylene-based discotic liquid crystals (DLCs) was synthesized and investigated in a systematic way to reveal the phase behavior and molecular dynamics. The later point is of particular importance to understand the charge transport in such systems which is the key property for their applications such as organic field effect transistors, solar cells or as nanowires in molecular electronics, and also to tune the properties of DLCs. The mesomorphic properties were studied by polarizing optical microscopy, X-ray diffraction, and differential scanning calorimetry, which were compared to the corresponding unfunctionalized DLC. The molecular dynamics were investigated by a combination of state-of-the-art broadband dielectric spectroscopy (BDS) and advanced calorimetry such as fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). Besides localized fluctuations, surprisingly multiple glassy dynamics were detected for all materials for the first time. Glassy dynamics were proven for both processes unambiguously due to the extraordinary broad frequency range covered. The α1-process is attributed to fluctuations of the alky chains in the intercolumnar space because a polyethylene-like glassy dynamics is observed. This corresponds to a glass transition in a confined three-dimensional space. The α2-process found at temperatures lower than α1-process, is assigned to the fluctuation of translational in plane movements of the triphenylene core inside distorted columns. This can be considered as a glass transition of a one-dimensional fluid. Therefore, obtained results are of general importance to understand the glass transition, which is an unsolved problem of condensed matter science.
The Dark Side of Science
(2019)
The Joint Summer School of the two Marie Skłodowska-Curie Innovative Training Networks (ITN) “BioCapture” and “GlycoImaging”, funded by the EU within the Horizon 2020 framework programme, which are both devoted to the development of new methods for cancer biomarker and cancer cell detection, will take place at the Adlershof Campus of BAM. 19 Early stage researchers of both projects will convene, discuss their own science and plan future collaborative research. Training in scientific writing (instructor: Luita Spangler, Free University of Berlin), an employability workshop (Antti Kapanen, University of Applied Sciences Berlin) and first contacts with the “dark side of science” (Brian R. Pauw, BAM) will complement the programme of the summer school.
Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with energy dispersive X-ray spectroscopy (EDS) at an SEM.
In der DIN EN ISO 14577 Metallische Werkstoffe – Instrumentierte Eindringprüfung zur Bestimmung der Härte und anderer Werkstoffparameter sind die Durchführung und Auswertung des Verfahrens, sowie die Kalibrierung der zu verwendenden Prüfmaschine genormt. In dieser Norm werden auch grundsätzliche Aussagen zur Bestimmung der Messunsicherheit gemacht.
An Beispielen aus der täglichen Prüfpraxis werden verschiedene Möglichkeiten, aber auch die Grenzen der Bestimmung der Messunsicherheitbei der Instrumentierten Eindringprüfung beschrieben und kritisch diskutiert.
Der Vortrag gibt den aktuellen Stand der Normung im Bereich der Oberflächentechnik insbesondere der Oberflächenanalytik und der Oberflächenmess- und -prüftechnik wider. Vorgestellt wird der Status technischer Berichte, Normenentwürfe und Normen u.a. zur Bewertung von Auflösung und Schärfe mit strahlbasierten Methoden im Nanometer- und Mikrometerbereich, zur Messung von Schichtdicken und Nanopartikeln in kritischen Dimensionen einschließlich Größen- und Formverteilungen mittels REM, zur Messung der Schichtdicke von Nanomaterialien und zur Klassifizierung von Kohlenstoffschichten mittels Ellipsometrie, zur Standardisierung der Ellipsometrie, zur Kalibrierung von Konfokalmikros-kopen für die Formmessung, zur linear elastisch dynamischen instrumentierten Eindringprüfung, zur Messung der flächenbezogenen Masse mittels AAS und ICP, zur Schichtpotentialmessung von Mehrfach-Nickelschichten, zur Schichtdicken und Flächen-widerstandsbestimmung sowie zur Bestimmung der Schichthaftung mittels Zentrifugentechnologie.
µ-FTIR spectroscopy is a widely used technique in microplastics research. It allows to simultaneously characterize the material of the small particles, fibers or fragments, and to specify their size distribution and shape. Modern detectors offer the possibility to perform two-dimensional imaging of the sample providing detailed information. However, datasets are often too large for manual evaluation calling for automated microplastic identification. Library search based on the comparison with known reference spectra has been proposed to solve this problem.
To supplement this ‘targeted analysis’, an exploratory approach was tested. Principal component analysis (PCA) was used to drastically reduce the size of the data set while maintaining the significant information. Groups of similar spectra in the prepared data set were identified with cluster analysis. Members of different clusters could be assigned to different polymer types whereas the variation observed within a cluster gives a hint on the chemical variability of microplastics of the same type. Spectra labeled according to the respective cluster can be used for supervised learning. The obtained classification was tested on an independent data set and results were compared to the spectral library search approach.
Synchrotron radiation sources with their unique properties in terms of intensity, polarization and adjustability offer a wide range of possibilities in materials research. A basic introduction about the creation and special properties of synchrotron radiation will be given. Examples of current work at BAMline, the high-energy measuring facility of the Federal Institute for Materials Research and Testing at the synchrotron BESSY, are used to illustrate the possibilities and limitations of existing measuring methods. It will be shown how the formation of corrosion layers can be tracked, how the abrasion of implants leads to the introduction of heavy metals into the surrounding bone matrix and how the detection of smallest impurities in gold is possible by optimizing the measuring conditions. Finally, an outlook at the hardware and software developments to be expected in the coming years is given.
In X-ray fluorescence (XRF), a sample is excited with X-rays, and the resulting characteristic radiation is detected to detect elements quantitatively and qualitatively. Quantification is traditionally done in several steps:
1. Normalization of the data
2. Determination of the existing elements
3. Fit of the measured spectrum
4. Calculation of concentrations with fundamental parameters / MC simulations / standard based
The problem with standard based procedures is the availability of corresponding standards. The problem with the calculations is that the measured intensities for XRF measurements are matrix-dependent. Calculations must, therefore, be performed iteratively (= time consuming) in order to determine the chemical composition.
First experiments with gold samples have shown the feasibility of machine learning based quantification in principle. A large number of compositions were simulated (> 10000) and analyzed with a deep learning network. For first experiments, an ANN (Artificial Neural Network) with 3 hidden layers and 33x33x33 neurons was used. This network learned the mapping of spectra to concentrations using supervised learning by multidimensional regression. The input layer was formed by the normalized spectrum, and the output layer directly yielded the searched values. The applicability for real samples was shown by measurements on certified reference materials.
No matter whether you are doing X-ray diffraction or scattering, at wide or small angles, in a lab or at a synchrotron, you will need a bespoke sequence of up to twenty different corrections before it gets about right (at our latest count). Our library now does this automatically and reliably to get you the data you deserve – in absolute units and with uncertainty estimates – without the pain. This talk will highlight the development of the modular library, the sequence and its foundation, show its applicability to real-world datasets, and highlight a possible way forward
Measurement of nanoparticle size (distribution) becomes a challenging analytical problem when non-spherical nanoparticles must be accurately measured. Most industrial nanoparticles have not only non-spherical shapes but also possess polydisperse size distributions, and due to their agglomeration/aggregation state are difficult (or even impossible) to be addressed individually. Moreover, driven by regulatory purposes related to the identification of a material as a nanomaterial, the accurate measurement of the smallest dimension of a (nano)particulate material makes the analysis even more complex.
In the first phase of the EU Project nPSize - Improved traceability chain of nanoparticle size measurements (https://www.bam.de/Content/DE/Projekte/laufend/nPSize/npsize.html), the efforts are focused on synthesis of nanoparticles of well-defined, non-spherical shape. Following candidates of reference materials (CRM) with certifiable particle size (distribution) are under characterization with respect to their homogeneity and stability: (i) titania nanoplatelets (10-15 nm thickness x 50-60 nm lateral), (ii) titania bipyramides (~60 nm length x 40 nm width), (iii) titania acicular particles (100 nm length x 15-20 nm width; aspect ratio 5.5/6), (iv) gold nanorods (~10 nm width x 30 nm length), and (v) gold nanocubes (~55 nm x 55 nm x 55 nm).
There are different ways how to prove the quality of the results obtained by electron microscopy and related microanalysis techniques, e.g. use of validated standard operation procedures, participation in proficiency testing exercises, use of certified reference materials, etc. International standards are able to provide requirements, specifications, guidelines or characteristics of methods, instruments or samples with the final goal that these can be used consistently in accredited laboratories. In the field of electron microscopy and microbeam analysis standardization and metrology are terms which are encountered rather seldom at major conferences and scientific publications. Nevertheless, spectra formats like EMSA/MSA for spectral-data exchange or tagged image file format (TIFF) for SEM, guidelines for performing quality assurance procedures or for the specification of X-ray spectrometers as well as of certified reference materials (CRMs) in EPMA, or measurement of average grain size by electron backscatter diffraction (EBSD), or guidelines for calibrating image magnification in SEM or TEM are ISO standards already published and used successfully by a large part of the electron microscopy and microbeam analysis community. A main and continuous task of ISO/TC 202 and its subcommittees is to identify and evaluate feasible projects/proposals needed to be developed into new international standards, particularly in respect to recent but established technology, such the silicon drift detector (SDD) EDS one.
Another international platform in the frame of which pre-standardization work can be organized is VAMAS (Versailles Project on Advanced Materials and Standards). International collaborative projects involving aim at providing the technical basis for harmonized measurements, testing, specifications, and standards to be further developed at ISO level. One key point of VAMAS activities is constituted by inter-laboratory comparisons for high-quality data. In the field of microbeam analysis, the technical working area (TWA) 37 Quantitative Microstructural Analysis deals with corresponding projects. Good ideas, e.g. on analysis of low-Z materials/elements and at low energies are particularly encouraged by directly contacting the author. Support and already available guidance will be supplied.
Outline
- maging ellipsometry: oncept and setup
- Basic theory: ellipsometry on tilted/curved surfaces
- Geometric considerations
- Tilt-induced cross-polarization
- Application: coating analysis on microlensarray
- Mueller-Matrix Imaging
- Conversion to Delta-Psi Image
- Layer-thickness of ITO coating
How to write your thesis
(2019)
The SAWG was established as an ad-hoc working group in 2003 before being established as a permanent working group. The first comparison was in 2007. Dr Unger recalled the terms of reference for the group, which paralleled those of the CCQM itself, with a focus on spatially resolved chemical surface analysis at the micro- and nano-scale. The group also had a remit to act as a forum for exchange of information on research and development of surface analysis, establish contact with relevant stakeholders and promote the development of SI traceable chemical surface measurements. The group currently had participants from 18 institutes, although five had not sent participants to recent meetings.
Reporting progress on studies, Dr Unger said that P-190CCQM-K-157 (measurement of HfO2 in thin film) had been completed, and the subsequent K-157 approved is ongoing and that for CCQM-K153 (Measurement of Specific Adsorption of N2 and Kr on nonporous SiO2 at liquid nitrogen temperature by BET) was at the draft B was completed stageand distributed to CCQM WG chairpersons for approval.
Dr Unger reported that CCQM-K-153 had covered measurement of specific absorption of nitrogen or krypton on nonporous silica at liquid nitrogen [ambient] temperature. This included an application of the BET method, a standard method for determination of surface area. This fitted into the ‘nonporous’ region of the SAWG measurement space, which included microporous, mesoporous and microporous regions. Of these regions, CCQM-K136 and CCQM-K153 demonstrated capability in meso- and microporous media respectively. CCQM-K153 involved two measurands; amount of absorbed gas at liquid nitrogen temperature, expressed as specific absorption, and the BET surface area. Specific absorption could in principle be traceable to the SI; BET was operationally defined. Five institutes participated. A detailed uncertainty budget was available for both measurands. Results had been excellent, with all laboratories agreeing well within their uncertainties and all in agreement with the reference value.
Reporting on CCQM P190, Dr Unger described the study objective measurand (amount of substance of HfO2 in a thin film), samples and methods. After showing transmission electron microscope images obtained in the study, he briefly reviewed the conclusions. The study identified a need to handle carbon contamination, harmonise the XPS measurement protocol, determine emission angle and identify a consensus value for attenuation length. These conclusions had informed the design of the proposed ongoing K157 study approved at the 24th Meeting of te CCQM.
The group planned a number of comparisons for the next three years:
2019: A pilot study on the amount of substance in a thin organic layer (previously approved).
2020: CCQMK-157, Measurement of the amount of substance of HfO2; A Key comparison on specific gas adsorption on microporous samples and a Pilot study on Homogeneous surface composition of an ionic liquid.
2021: A key comparison measuring the amount of substance in a thin organic layer.
Dr Unger additionally described a recently proposed pilot study to examine chemical composition in a deep nanoscale layer. This was important for the electronics industry. Four participants had expressed interest. The measurand will be the amount of Ir(ppy)2(acac) in a thin organic layer within an organic layer stack on a silicon substrate. He also reported that SAWG had started work on characterisation of graphene material grown by chemical vapour decomposition (CVD). The work would examine coverage on the substrate, number of layers, level of disorder, uncertainty budgets associated with the measurement, and data analysis. A link to VAMAS Technical Work Area 41 “Graphene and Related 2D Materials“ would also be established.
Looking forward, Dr Unger said the group had established a task group on application of Raman spectroscopy. This had important applications but was currently seen as qualitative. He presented the terms of reference for the task group for approval by the CCQM.
Dr Unger reviewed the SAWG activities that have progressed the state of the art in measurement science. He listed the past and ongoing comparisons that had addressed new and challenging measurement problems, and drew attention to a number of key publications in surface analysis. He additionally described stakeholder engagement activities, including collaboration with VAMAS, input to ISO TC 201, contributions to Euramet projects, and contributions to two recent stakeholder workshops.
Everything SAXS
(2019)
Up until several years ago, tensile and compressive tests have been exclusively carried out as single-sample tests within a tensile, hardness or universal testing machine. The availability of centrifuge technology changed this situation in 2013 in several ways because centrifugal force is used as testing force within a rotational reference frame.
Firstly, multiple-sample strength testing became feasible for both tensile load condi-tions, e.g. determination of composite, bonding or adhesive strength, and compressive load conditions, e.g. hardness, compressibility and compactibility. Secondly, there is no need for a two-sided sample clamping and double-cardanic suspensions as samples are simply inserted using a one-sided sample support. Thirdly, shear forces can be avoided by means of guiding sleeves which steer test stamps acting as mass bodies for either tensile or compressive testing. Fourthly, up to eight samples can be tested under identical conditions within a very short period of time, typically within 15 minutes including sample loading and unloading. Hence, either a reliable statistics (of identical samples) or a ranking (of different samples) can be derived from one test run.
The bench-top test system is described in detail and demonstrated that centrifugal force acts as testing force in an appropriate way because Euler and Coriolis force do not affect the testing results. Examples for both tensile strength testing, i.e. bonding strength of adhesives-bonded joints and adhesive strength of coatings, and compres-sive strength testing, i.e. Vickers-, Brinell- and ball indentation hardness and deter-mination of spring constants, are presented, discussed and compared with conven-tional tests within tensile, hardness or universal testing machines.
At present, a maximum testing force of 6.5 kN can be realized which results at test stamp diameters of 5 mm, 7 mm, and 10 mm in tensile or compressive stress values of 80 MPa, 160 MPa, and 320 MPa. For tensile strength, this is already beyond bonding strength of cold- and warm-curing adhesives. Moreover, centrifuge technology is compliant to standards such as EN 15870, EN ISO 4624, EN ISO 6506/6507 and VDI/VDE 2616. Programmable test cycles allow both short-term stress and log-term fatigue tests. Based on a variety of examples of surface and bonding technology, applications in both fields R&D and QC are presented. Meanwhile, centrifuge technology is also accredited according to DIN EN ISO/IEC 17025.
Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge for modern analytical techniques and requires approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by spectroscopic ellipsometry (SE).
Mesoporous iridium oxide - titanium oxide (IrOx-TiOx) films were prepared via dip-coating of a solution containing a triblock-copolymer as structure-directing agent, an iridium precursor as well as a titanium precursor in ethanol. Deposited films with different amounts of iridium (0 wt%Ir to 100 wt%Ir) were synthesized and calcined in air. The thin films were analyzed with SE using the Bruggeman effective medium approximation (BEMA) for modelling. The results were compared with electron probe microanalysis (EPMA) as part of a combined SEM/EDS/STRATAGem Analysis.
In the last years, the implementation of imaging ellipsometry in the variety of optical characterization techniques has shown tremendous potential to analyze the topology of surfaces in the lateral dimension. In the later studies, this contrast-rich surface images were affiliated with changes of the refraction indices, Absorption bands or layer thicknesses. However, it was realized that additional factors like curvature or scattering can have a great Impact on the ellipsometric readout of the analyzed system. In this study, we focus on the systematic evaluation of structural anomalies and inhomogenities of several Basic systems. This includes spherical particles as a model for microscopic curved surfaces in a range of 0.25 to 25 μm in diameter. In the macroscopic regime several conventional convex lenses were analyzed. Additional affords were made to generate microscopic concave model systems by applying nanoindentation with a spherical indentation unit. With this method calottes with a depth of 0.04 to 2 μm and radius of 2.5 μm were made. The macroscopic counterpart is delivered by conventional concave lens systems. For all systems, a variety of different bulk materials was investigated. This includes metal oxides, metals and polymers as well as combinations of each by applying coatings on the bulk materials with different layer thicknesses.
To analyze these structural anomalies and inhomogenities properly, Mueller-Matrix imaging ellipsometry is the method of choice to address cross- and depolarization effects that occur due to the curved surfaces.
Supplementary methods were used for an independent characterization of the topological properties of all structural anomalies and inhomogenities. This includes AFM and SEM for the microscopic samples (microparticles and nanoindented holes) and white light interferometry for the macroscopic lenses.
This study results in a systematic screening of different coated and uncoated material systems with a topology that does not fit into conventional ellipsometry and thus is analyzed by Muller-Matrix imaging ellipsometry. This will help in quality control and is a contribution to the understanding of the polarizing effects of non-ideal Systems analyzed by ellipsometry.
The presentation points out and discusses potential future projects on microbeam analysis which shall benefit from the pre-standardisation platform VAMAS (Versailles Project on Advanced Materials and Standards) which is basically related to Organisation and participation in international inter-laboratory comparisons. Ideas and strategies of better synergies between VAMAS and ISO projects (including promotion and a dedicated liaison) are discusssed.
The Systematic Review of ISO/DIS 15632 Selected Instrumental Parameters for the Specification and Checking of Energy-Dispersive X-Ray Spectrometers for Use in Electron Probe Microanalysers is discusssed. Zero strobe peak, better description of dead-time and of the pulse-processing electronics are the major issues under discussion.
Nowadays, different nanoparticles have been developed for commercial applications. However, since data on toxicity are barely available, their increasing application in cosmetic products, food and their release in the environment might cause severe problems. Since a range of physical, chemical, and biological characteristics of NPs are closely related to particle size and surface functionalization, precise separation and surface groups quantification is essential to acquire an in-depth understanding of their properties.
In this work, the performance of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for the separation of nanoparticles (NPs) with different sizes, coatings, and coating densities was investigated and optimized.
For the first time, a two-dimensional off-line hyphenation of both techniques (AF4-CE) was developed. The results clearly demonstrated, that AF4-CE hyphenation can significantly improve the separation resolution and reduce the peak broadening in CE. Also, for the first time, CE was employed to determine the coating density of NPs and the results were in good agreement with the values acquired with conductometric titration.
Crystalline molecular materials with mechanical flexibility are promising for technological development. This is particularly true for the development of advanced materials with optoelectronic and biomedical applications. While a growing number of mechanically flexible crystalline molecular materials are being reported,1 they remain scarce. At present, most discoveries are serendipitous, as limited design strategies are currently known. Amongst these strategies Desiraju et. al. suggested that elastic materials must contain herringbone structures.2 For plastic crystals, the so-called ‘shape-synthon’ strategy has been developed, in which weak non-covalent interactions are introduced into structures to facilitate mobility of molecules.3 This includes formation of slip planes. Generally, these models have performed very well at predicting and rationalizing the mechanical properties of new materials. Recently, however, a family of one-dimensional covalent networks (coordination polymers; CPs) has been described, which show mechanical elasticity. With drastically different structural chemistry, these systems do not seem to adhere to the currently established rules. Herein, we present the first such system: a plastically bendable crystal of a 1D CP, [Zn(-Cl)2(3,5-Cl2Py)2]n (where 3,5-Cl2Py = 3,5-dichloro pyridine). This CP crystallizes in a tetragonal, and can therefore be bent over two major faces to acute angles without fracturing. We conducted bending and indentation experiments to quantify the mechanical properties of the CP crystal. This was complimented by Vibrational (Raman and Terahertz) spectroscopy and theoretical calculations for deeper understanding of molecular level structural deformation.
Neuartige Materialien, die bekannte (Werk-)Stoffe mit neuen Funktionalitäten ausstatten, spielen eine zunehmend wichtige Rolle im Bereich der Materialforschung und -prüfung. Das Spektrum neuartiger Materialien reicht von der gezielten Oberflächenfunktionalisierung und -strukturierung makroskopischer Materialien, dünnen Beschichtungen bis hin zu mikro- und nanoskaligen Kompositmaterialien und funktionalen Materialien an der Schnittstelle zur Biologie, Biotechnologie, nachhaltige Energiespeicherung und Sensorik. Dabei bieten neuartige Materialien die Chance, Werkstoffe und Produkte mit erweiterter oder verbesserter Funktionalität zu erhalten und Sicherheit bereits im Designprozess zu berücksichtigen. Durch dieses breite Anwendungsspektrum und die Herausforderungen, die solche Materialien für die Sicherheit in Chemie und Technik mit sich bringen, sind diese in allen Themenfeldern der BAM repräsentiert (Material, Analytical Sciences, Energie, Infrastruktur und Umwelt).
Die Aufgaben der BAM erstrecken sich dabei von der Herstellung von Referenzmaterialien für Industrie, Forschung und Regulation, über die Erstellung von standardisierten Referenzverfahren für nachhaltige Messungen im Umwelt- und Lebenswissenschaftsbereich bis hin zur Bereitstellung von belastbaren und zitierbaren Referenzdaten. Durch die genaue Charakterisierung neuartiger Materialien können potentiell problematische Substanzen identifiziert und deren Risiken besser abgeschätzt werden. In diesem Beitrag werden einige aktuelle Beispiele aus diesen Bereichen vorgestellt.
Polymers at interfaces play a major role in a broad variety of applications ranging from engineering purposes (for instance polymer based nanocomposites) to high tech implications (for instance light emitting diodes).
Here, thin films with thicknesses down to few nanometers are prepared on different substrates as model systems for polymer composites. The thin films are investigated by a combination of surface analytical and volume sensitive methods. As surface analytical methods atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements (CAM) are employed. As volume sensitive broadband dielectric spectroscopy (BDS), specific heat spectroscopy (SHS), and ellipsometry are used. Especially attention is paid to understand the glass transition behavior of thin films because the glass transition is the key phenomenon determines the application of polymers also in thin films.
To understand the glass transition behavior of thin films, which is controversially discussed in literature, a three layer model is discussed. Firstly, a mobile surface layer is assumed at polymer air interface of the film due to missing of segment/segment interactions. Secondly, in the middle of the film a bulk-like layer should be expected. Thirdly, for polymers having non-repulsive interactions with the substrate an irreversibly adsorbed layer is expected to be formed. Due the adsorption the molecular mobility of the segments in this layer is slowed down. What is measured for the glass transition of thin films is a complicated average of all of these effects. The different layers are hardly to address separately. Therefore, in the presentation especially model systems are selected and investigated to verify the layer model.
Mechanochemistry is a fast and efficient method applicable for the synthesis of new organic, metal-organic, and inorganic compounds. The direct monitoring of milling reactions is still challenging. The underlying reaction mechanisms remain often unclear. In the last years, have established a tandem in situ approach for investigating mechanochemical reactions using time-resolved in situ XRD coupled with Raman spectroscopy. Here, we present an in situ coupling of synchrotron XRD, Raman spectroscopy, and thermography allowing the observation of mechanochemical reactions in real time. Information on the crystalline, molecular, and temperature state of the materials during grinding could be collected. The chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. Furthermore, the presented setup allows the detection of crystalline, amorphous, eutectic as well as liquid intermediates. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key for future optimization of mechanochemical syntheses.
What exactly does a postdoc do at a research institute? What scientific questions does he or she want to address? What is their daily work routine? During our regular Lab Tours, female postdocs provide insight into their jobs. They also tell us about their career path: How did they get there? And what do they envision for their professional future?
This time, Dr. Ana Guilherme Buzanich, a scientist from the Structure Analysis division at the Bundesanstalt für Materialforschung und -prüfung (BAM), will give an overview of her Research areas. She works at the electron storage ring BESSY-II where she conducts experiments at two hard X-ray beamlines (BAMline and µSpot). The tour includes a guided visit of the research facility.
Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF.
Visualisierung von mikro- und nanoskalierten Oberflächenstrukturen mittels abbildender Ellipsometry
(2019)
In den letzten Jahren hat die Einbindung der abbildenden Ellipsometrie in die Gruppe der optischen Verfahren zur Oberflächencharakterisierung ein enormes Potential bei der Analyse von topologischen Strukturänderungen gezeigt. Der dabei abgebildete Kon-trast wurde typischerweise auf Änderungen im Brechungsindex, Absorptionseffekte oder Schichtdickenänderungen zurückgeführt. In späteren Studien wurde festgestellt, dass auch andere Faktoren, wie etwa die Krümmung der Oberfläche oder Kanten von Struktu-ren einen signifikanten Einfluss auf die Messung der ellipsometrischen Paramater haben. Um diese Effekte aus der ellipsometrischen Messung extrahieren zu können, wird auf die Analyse der Müller-Matrix zurückgegriffen.
In dem hier vorliegenden Beitrag wird gezeigt, wie die Müller-Matrix-Imaging Ellipsomet-rie (MM-IE) zur Charakterisierung von Oberflächenstrukturen verwendet werden kann. Dazu werden mikro- und nanoskaliert gekrümmte Oberflächen zunächst mit verschiede-nen Referenzmethoden, wie Rasterelektronenmikroskopie (SEM), Lichtmikroskopie (OM), Weißlichtinterferenzmikroskopie (WLIM) und Rasterkraftmikroskopie (AFM) vali-diert erfasst. Der anschließende Vergleich mit den Ergebnissen der Müller-Matrix-Ima-ging-Ellipsometrie ermöglicht eine Korrelation der zugrunde liegenden Strukturphäno-mene mit den ellipsometrischen Daten. In diesem Artikel wird das Prinzip an drei industriell relevanten Strukturgruppen demonstriert: Sub-Mikropartikel, Mikropartikel und sub-mikroskalierte Vertiefungen.
X-ray absorption fine structure (XAFS) spectroscopy is a powerful and widely used tool for material characterization. It is non-destructive, element-sensitive and requires no long-range order of the sample, making it suitable for the investigation of amorphous phases. XAFS includes the X-ray absorption near edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS), providing information about the electronical state of the absorbing atom and the spatial order of the neighboring atoms respectively.
Our new approach presented here is derived from the classical dispersive XAFS setup. The aim is to have a scanningless, stable and reproducible setup for applications, in which dynamic processes occur in the second time scale.
A broad polychromatic beam passes through the sample and is dispersed afterwards by a convexly bent Si (111) crystal. All energies are reflected under different angles and thus spatially separated, allowing a position sensitive detector to record a spectrum over the energy range of the incoming beam in a single shot.
Tests of this setup were performed at the BAMline @ BESSY-II (Berlin, Germany) with different metal foils. First in situ measurements comprised the investigation of the early stages of the zinc(II)2-methylimidazolate (ZIF-8) crystallization. This topic of metal-organic-frameworks (MOF) research is of interest for medical applications. Structural changes with a time resolution of 1 s could be followed. The second dimension of the broad beam can be used for a lateral resolution.
Der Vortrag widmet sich der „CAT-TECHNOLOGIE ZUR BESTIMMUNG DER HAFTFESTIGKEIT DÜNNER SCHICHTEN“ und beschreibt die Punkte „Motivation –CAT-Technologie“ (CAT: Centrifugal Adhesion Testing) und die „Haftfestigkeit von Schichten“, (Ag-Schichten auf N-BK7 Glas, Cr- und Al-Schichten auf Borofloat 33 Glas, Au-Schichten auf N-BK7 Glas und SiO2-Schichten auf CR39 Polymer) im Einzelnen.