TY - JOUR A1 - Rossi, Andrea A1 - Corrao, Elena A1 - Alladio, Eugenio A1 - Drobne, Damjana A1 - Hodoroaba, Vasile-Dan A1 - Jurkschat, Kerstin A1 - Kononenko, Veno A1 - Madbouly, Loay Akmal A1 - Mrkwitschka, Paul A1 - Yasamin, Nakhli A1 - Novak, Sara A1 - Radnik, Jörg A1 - Saje, Špela A1 - Santalucia, Rosangela A1 - Sordello, Fabrizio A1 - Pellegrino, Francesco T1 - Multivariate optimization and characterization of graphene oxide via design of experiments and chemometric analysis N2 - Controlling the structure and properties of graphene oxide (GO) remains a challenge due to the poor reproducibility of conventional synthetic protocols and limited understanding of parameter-property relationships. In this study, we present an integrated analytical framework that combines Design of Experiments (DoE) with chemometric modelling to systematically assess the effects of eight synthesis variables on GO’s physicochemical and functional features. A Plackett–Burman experimental design enabled efficient screening of synthesis conditions, while comprehensive characterization (spanning UV–Vis spectroscopy, XPS, SEM–EDX, TEM–EDX, and XRD) was coupled with multivariate tools (Principal Component Analysis and Multiple Linear Regression) to identify statistically significant correlations between synthetic inputs and material responses. Notably, we demonstrate that UV–Vis spectra can serve as a robust proxy for oxidation state, offering a rapid and accessible alternative to surface-sensitive methods. The approach yields a predictive analytical toolkit for guiding GO synthesis and highlights a generalizable strategy for the rational design of flat nanomaterials. This work supports reproducible, resource-efficient material development aligned with Safe and Sustainable by Design (SSbD) principles. KW - Graphene oxide KW - 2D-materials KW - Design of Experiment KW - Synthesis KW - Chemometric analysis PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652576 DO - https://doi.org/10.1016/j.flatc.2025.100988 SN - 2452-2627 VL - 55 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Thünemann, Andreas A1 - Radnik, Jörg A1 - Häusler, I. A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Iron Oxide Nanocubes as a New Certified Reference Material for Nanoparticle Size Measurements N2 - The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes’ edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators. KW - Certification KW - SAXS KW - Homogeneity KW - Nano KW - Particle KW - Iron oxide KW - Quality assurance KW - Reference material KW - Size KW - Electron microscopy KW - Stability KW - Shape PY - 2023 DO - https://doi.org/10.1021/acs.analchem.3c00749 SN - 0003-2700 VL - 95 IS - 33 SP - 12223 EP - 12231 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-58176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ankli, P.P. A1 - Ali, A. A1 - Hodzic, S. A1 - Logachov, A. A1 - Maciejczuk, K. A1 - Milochiv, A. A1 - Hardy, S. A1 - Hardy, B. A1 - Novak, S. A1 - Kranjc, E. A1 - Kononenko, V. A1 - Saje, S. A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg A1 - Akmal, Loay A1 - Mrkwitschka, Paul A1 - Pellegrino, F. A1 - Rossi, A. A1 - Alladio, E. A1 - Sordello, F. A1 - Gulumian, M. A1 - Valsami-Jones, E. A1 - Andraos, C. A1 - Wepener, V. A1 - Jurkschat, K. A1 - Jones, E. A1 - Singh, D. A1 - Ibrahim, B. A1 - van der Zande, M. A1 - Fernandez-Poulussen, D. A1 - Queipo, P. A1 - Drobne, D. T1 - Data management for image-based characterisation of 2D nano-materials N2 - The ACCORDs project, funded through Horizon Europe, is pioneering a novel approach to investigate Graphene Family Materials (GFMs) through image analysis. Our aim is to unveil how these materials might influence health and the environment. To achieve this, we are developing a platform designed for the easy retrieval, access, sharing, and utilisation of GFM data and the coordination between biological and physico-chemical data formats. Integral to this platform is an OMERO-based library for image storage, alongside data collection forms and image analysis tools. Efforts are underway to streamline the process for researchers to upload and disseminate their findings, manage information within a database and navigate the data with ease. Adhering to REMBI guidelines, which set the standard for annotating biological images with metadata, we ensure our data collection is comprehensive and adheres to established best practices. Initially, we are employing thresholding and basic machine learning techniques for image segmentation, laying the groundwork for advanced analysis through deep learning to gain more profound insights. Upon completion, the project will deliver a comprehensive platform facilitating efficient data and image management concerning GFMs. This platform will enable the straightforward discovery and use of protocols and results, all organised in accordance with the FAIR principles – Findable, Accessible, Interoperable, and Reusable. This initiative is poised to significantly impact materials science, enhancing our comprehension of the safety and environmental implications of 2D materials. KW - Graphene KW - Image analysis KW - Data management PY - 2024 DO - https://doi.org/10.1016/j.toxlet.2024.07.655 VL - 399 SP - S271 PB - Elsevier B.V. AN - OPUS4-61011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Rühle, Bastian A1 - Kuchenbecker, Petra A1 - Löhmann, Oliver A1 - Lindemann, Franziska A1 - Hodoroaba, Vasile-Dan T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed. KW - Nanopowder KW - Electron microscopy KW - Sample preparation KW - Cross-sectioning KW - Cerium oxide KW - Zinc oxide PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289 DO - https://doi.org/10.1038/s41598-023-51094-0 SN - 2045-2322 VL - 14 SP - 1 EP - 10 PB - Springer Nature CY - London AN - OPUS4-59328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Mrkwitschka, Paul A1 - Moos, R. A1 - Rabe, Torsten T1 - Glass-ceramic composites as insulation material for thermoelectric oxide multilayer generators N2 - Thermoelectric generators can be used as energy harvesters for sensor applications. Adapting the ceramic multilayer technology, their production can be highly automated. In such multilayer thermoelectric generators, the electrical insulation material, which separates the thermoelectric legs, is crucial for the performance of the device. The insulationmaterial should be adapted to the thermoelectric regarding its averaged coefficient of thermal expansion α and its sintering temperature while maintaining a high resistivity. In this study, starting from theoretical calculations, a glass-ceramic Composite material adapted for multilayer generators fromcalciummanganate and Calcium cobaltite is developed. The material is optimized towards an α of 11 × 10−6 K−1 (20–500◦C), a sintering temperature of 900◦C, and a high resistivity up to 800◦C. Calculated and measured α are in good agreement. The chosen glass-ceramic composite with 45 vol.% quartz has a resistivity of 1 × 107 Ωcm and an open porosity of <3%. Sintered multilayer samples from tape-cast thermoelectric oxides and screen-printed insulation show only small reaction layers. It can be concluded that glass-ceramic composites are a well-suited material class for insulation layers as their physical properties can be tuned by varying glass composition or dispersion phases. KW - Electrical insulators KW - Glass-ceramics KW - Multilayers KW - Thermal expansion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538898 DO - https://doi.org/10.1111/jace.18235 SN - 0002-7820 SP - 1 EP - 10 PB - Wiley Online Library AN - OPUS4-53889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Madbouly, Loay Akmal A1 - Mrkwitschka, Paul A1 - Stockmann, Jörg Manfred A1 - Jones, Elliot A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Comparative Elemental Analysis of Commercial Functionalized Graphene Nanoplatelets Along the Production Chain With X‐Ray Photoelectron and Energy‐Dispersive X‐Ray Spectroscopy N2 - Graphene has been commercialized for over a decade, primarily in the form of suspensions and inks. In this study, we investigate the properties of graphene nanoplatelets (GNPs) and their functionalized derivatives, incorporating fluorine or nitrogen as functional groups (FG). The analysis was conducted on three forms, that is, powders, suspensions, and inks, using X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy‐dispersive X‐ray spectroscopy (EDX). The objective of this work is to establish a rapid and comprehensive systematic approach for elemental analysis of commercial functionalized graphene, which can be used for quality control. Functionalization is employed to tailor the material's physical and chemical properties. In our study, graphene samples, functionalized with fluorine or ammonia in a plasma reactor, were investigated. Both XPS and EDX were applicable for all three forms and showed, in general, similar trends between the three forms, so that both XPS and EDX can be used for quality control of GNPs along the production chain. KW - Commercial graphene KW - Functionalized graphene KW - Graphene inks KW - SEM/EDS KW - XPS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625752 DO - https://doi.org/10.1002/sia.7386 SN - 1096-9918 SP - 1 EP - 7 PB - Wiley AN - OPUS4-62575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Sahre, Mario A1 - Corrao, Elena A1 - Pellegrino, Francesco A1 - Alonso, Beatriz A1 - Zurutuza, Amaia A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Standardized Elemental Composition Analysis of Graphene‐Related 2D Materials (GR2M) With SEM/EDS and XPS Works Reliably N2 - Reliable quantification of the chemical composition of graphene‐related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as X‐ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP‐MS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) are recommended by standardization bodies. The specific parameters to be measured are also defined, e.g., the oxygen‐to‐carbon (O/C) atomic ratio, the trace metal impurities, or the functional groups. In this contribution, for the first time, results of a systematic study on the capability of energy‐dispersive X‐ray spectroscopy (EDS) at a scanning electron microscope (SEM) to reliably quantify the O/C ratio and impurities remained from the synthesis of selected GR2M are reported. The robustness of SEM/EDS analysis is verified for various measurement conditions (different excitations and EDS detectors) and the validity of the results is tested by comparison to the established XPS analysis. Moreover, an ionic liquid is used as a reference material for the quantification of the light elements such as C, N, O and F. The study clearly demonstrates the reliability of the fast and widely available SEM/EDS as a standard method for the quantification of the elemental composition of GR2M and generally of light materials. KW - Graphene oxide flakes KW - Impurities KW - O/C ratio KW - SEM/EDS KW - Standard KW - XPS PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656748 DO - https://doi.org/10.1002/smll.202511283 SN - 1613-6810 SP - 1 EP - 10 PB - Wiley-VHC GmbH AN - OPUS4-65674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -