TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Morphology Analysis of Graphene Oxide Flakes with SEM - Preparation of an Inter-Laboratory Comparison @VAMAS N2 - Experience gained at BAM within the European project ISGScope on the accurate measureemnt of graphene oxide flakes by electron microscopy is presented. Particularly, factors such as the type of solvent, substrate temperature, but also proper, gentle measurement parameters and image analysis conditions towards automation are highlighted. The measurement procedures in develeopment are being prepared to launch an inter-laboratory comparison under VAMAS (TWA41) as preparatory guidance for future standardisation at ISO. T2 - ISO/TC 229 Nanotechnologies Plenary Meeting - Graphene Standardisation CY - Teddington, UK DA - 14.11.2022 KW - Graphene oxide flakes KW - SEM KW - Morphology KW - VAMAS KW - Standardisation KW - Sample preparation KW - ISOGScope PY - 2022 AN - OPUS4-56300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul T1 - Wire-print procedure for accurate morphological and Chemical characterization of graphene-related 2D-materials N2 - One of the biggest challenges in the physico-chemical characterization of particulate nanomaterials pertains to the sample preparation. Particularly the imaging methods require suitable deposition of the sample on a substrate. ‘Suitable’ sample preparation of a particulate (nano)material on a substrate means to make visible the constituent particles to a microscopy technique able to analyze the nanoscale (AFM, SEM, TEM, etc). The particles deposited on a substrate either directly as a powder or from liquid suspension must be ideally isolated (de-agglomerated), without particle losses, homogeneously distributed in a high density of particles per substrate area for efficient analysis, with good statistics of the counted particles. Various sample preparation approaches to meet the latter requirements have been reported in the literature, e.g. electrospray, substrate surface treatment, embedding the particulate material and polishing the cross-section, or addition of ligands to the suspended nanostructures to enhance their hydrophilicity [1], [2], [3], [4]. In this study we have systematically tested the efficacy of a new deposition procedure for graphene-related 2D materials (GR2M’s) from liquid suspension onto a substrate for quantitative analysis of their size and shape distribution with electron microscopy. The technique is an extension of the conventional drop-casting method, and we have designated it “wire-print” deposition. It consists of two steps, first one being usual drop-casting on a copper substrate and second one involving a thin copper wire with a sub-mm diameter being dipped into the deposited droplet and retracted with a corresponding half-spherical droplet attached on its tip and final deposition of this entire nL-amount of suspension onto e.g. a silicon wafer for microscopical, detailed analysis. The result of 11 series of such a wire-print deposition for a graphene-based ink is shown in Figure 1 (labeled A-L), where various conditions (treatment of the starting suspension) have been experimented with a repetition of up to 10 times per condition, all together 86 spots on a silicon wafer of 10 mm x 10 mm. The result of one series of 8 repeated wire-print depositions is shown in Figure 2, where the deposited spots are visualized with SEM. Note the weak presence of coffee-rings, irregular spot shape, and presence of agglomerates. The results for the measured flake size distribution expressed as ECD (equivalent circular diameter) are represented in Fig. 3 for all the eight depositions. Both the mean value of the 8 ECD distributions and the total number of flakes deposited in each spot show a variance in the range of 17% and 22%, respectively, see Table 1. In the context of accurate analysis of such challenging complex materials these numbers can be considered as excellent and demonstrate the high benefit of the wire-print deposition for accurate morphological measurements on GR2M’s. T2 - Microscopy and Microanalysis 2025 CY - Salt Lake City, UTAH, USA DA - 27.07.2025 KW - Sample preparation KW - Graphene KW - Electron Microscopy KW - Morphology PY - 2025 AN - OPUS4-64083 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -