Electrophoretic deposition of silver from organic PDADMAC-stabilized suspensions

This study on the electrophoretic deposition (EPD) of silver particles illustrates the influence of the electric field strength on the surface morphology of the deposit. Experiments were performed in ethanol- and methylethylketone (MEK)-suspensions under a direct electric field ranging from 50 to 360 V/cm. The charging agent PDADMAC (poly-(diallyldimethyl)-ammonium-chloride) proved to have a good electrostatic stabilizing effect in both systems and led to a positive zeta-potential in EtOH and to negatively charged particles in MEK. The yield of the deposits showed a linear relation with electric field strength which agrees with Hamakers law for the kinetic of EPD. Layers deposited at low electric field strengths exhibited a smooth and plane surface. Values higher than 180 V/cm resulted in the formation of parallel grooves. The morphology changed again at fields exceeding 360 V/cm and exhibited irregularly distributed hillocks.