TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Yamamoto, K. A1 - Grulke, E. A. T1 - Size and shape distribution of bipyramidal TiO2 nanoparticles by transmission electron microscopy – an inter-laboratory comparison JF - Microscopy and Microanalysis N2 - Extraction of true, 3D shape (and size) of non-spherical nanoparticles (NPs) is associated with errors by conventional 2D electron microscopy using projection images. Significant efforts within the ISO technical committee TC 229 ‘Nanotechnologies’ are aimed at establishing accurate TEM and SEM measurement of NP size and shape as robust, standard procedures. Study groups have been organizing inter-laboratory comparisons on well-selected NP systems according to the market needs, such as aggregated titania nano-powder for which size and shape distribution of primary crystallites of irregular shape must be measured accurately. To be noticed is e. g. the fact that the measurement procedure allows only manual selection of the particles clearly distinguishable for analysis as well as manual definition of the contour of the imaged NPs. An inter-laboratory exercise on titania NPs (pure anatase, grown by hydrothermal synthesis) of well-defined non-spherical shape, i.e. bipyramidal has been recently started within ISO/TC 229 under similar conditions as for the irregular shaped titania. Overlapped particles were allowed to be considered, as long as they are clearly distinguishable. One decisive NP selection criterion was to analyze only those NPs with a roundness value below 0.7, i.e. the NPs laying on the support foil and, hence, with projection areas clearly deviating from perfect circles (R=1). The overall evaluation (for 15 labs) of the size descriptors (area, Feret, minFeret, perimeter) and shape descriptors (aspect ratio, roundness, compactness, extent) by analysis of variance is just to be finished and included in ISO/WD 21363 Nanotechnologies -- Protocol for particle size distribution by transmission electron microscopy. KW - Nanoparticles KW - Electron microscopy KW - Titanium oxide KW - Particle size distribution PY - 2018 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/size-and-shape-distribution-of-bipyramidal-tich-nanoparticles-by-transmission-electron-microscopy-an-interlaboratory-comparison/9E2FA0C716DB5F881E3032D014DFD52B DO - https://doi.org/10.1017/S1431927618009017 SN - 1431-9276 SN - 1435-8115 VL - 24 IS - S1 (August 2018) SP - 1706 EP - 1707 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-46005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -