Study of the nanoparticle/microparticle powder systems by dry dispersion

The study of a nanoparticle/microparticle powder systems by dispersion of different type of nanoparticles over microparticles, as support or substrate, has been afforded by a soft mechanical and solvent-less procedure and its effect on the electrostatic charge was studied. The dispersion degree can be evaluated by using diffuse reflectance measurements due to the non-linear change of the reflectance as a function of the nanoparticles amount in the powder composite. The maximum slope variation of the non-linear curve revealed the point where the nanodispersion attained the highest efficiency. The interaction between the OH groups of the dissimilar surfaces provides the anchoring mechanism of the nanoparticles onto the microparticles and the net charge compensation. Furthermore, the dispersed and anchored nanoparticles provide a roughness increasing of the microparticles surface that is responsible for a formation of nanoparticle/microparticle composite powders in which tribo-charge maximized due to the enhancement of composite packaging.