Methods for functionalization of microsized polystyrene beads with titania nanoparticles for cathodic electrophoretic deposition

Functionalization of colloidal particles based on the use of polyelectrolytes and heterocoagulation was combined with electrophoretic deposition (EPD), with the aim of depositing titania-polystyrene (TiO2-PS) composite particles on Ti6A14V substrates. The composite particles were obtained by heterocoagulation of TiO2 nanoparticles on the surface of monosized polystyrene beads of 4.6 mu m in diameter. Two alternative methods were developed for the preparation of the TiO2-PS suspensions in organic fluids for cathodic electrodeposition. The first method was carried out in alkaline aqueous medium with the use of polyelectrolytes and intermediate control measurements of zeta potential, conductivity, and pH; the second one was carried out directly in the organic solvent used for EPD, typically isopropanol. Examples of deposits obtained by EPD in both suspensions and a comparative analysis between the two methods are presented. (c) 2007 Elsevier Inc. All rights reserved.