Effet de la polydispersion des particles sur le diamètre équivalent issu de la mesure de VSSA : démonstration théorique et application à 8 poudres de diamètres de particules primaires moyens entre 9 et 130 nm

Volume Specific Surface-Area (VSSA) has been identified as a relevant and alternative method to electron microscopy to determine whether a material is or not a nanomaterial. VSSA is an integral measurement method that provides an indirect representation of particle size. When this conversion into particle diameter is carried out, primary particles are supposed to be monodisperse, which can be considered far from reality, materials being typically composed of polydisperse primary particles. The way particle polydispersion affects the VSSA of a material, and thus the equivalent particle diameter deduced, is investigated in this paper, where the case of normally-distributed, spherical primary particles, is considered. A theoretical study has led to the introduction of a correction polydispersionbased factor. From experimental VSSA data obtained for eight powders covering a range of primary particle mean diameters from 9 to 130 nm, the VSSA-based primary particle mean diameters were compared to the mean primary particle size obtained from electron microscopy analysis, considered as the reference method. Integrating primary particle polydispersion through the use of the correction factor improves the accuracy of particle size stemming from the VSSA approach, the relative discrepancies being within ± 20% from the reference diameter.