Identification of nanomaterials by the volume specific surface area (VSSA) criterion: application to powder mixes.

We demonstrate the relevance of the Volume Specific Surface Area (VSSA) parameter to identify the nanoparticulate character of powder mixes based on either spherical constituent particles with bimodal size distributions (TiO 2 ), or fiber-like constituent particles with unimodal size distributions (sepiolite and sepiolite-based pigments). These new results indicate that VSSA could reasonably be proposed as an optional criterion in the future for the definition of nanomaterials based on the European Commission recommendation, provided certain requirements are fulfilled.