Deposition of colloid particles on polyelectrolyte multilayers

Deposition of negatively and positively charged latex particles onto polyelectrolyte multilayers adsorbed at mica was studied experimentally by using the impinging-jet cell. These data were complemented by streaming potential measurements in the parallel-plate channel arrangement. Two types of polyelectrolytes were used: polyallylamine hydrochloride (PAH), of a cationic type and polysodium 4-styrenesulfonate (PSS) of an anionic type. The bulk characteristics of polymers is represented by the zeta potential values obtained from microelectrophoretic mobility measurements. It was shown that the initial deposition rates of polystyrene latex on oppositely charged polyelectrolyte layer attained the limiting value characteristic for homogeneous surface. On the other hand, the initial deposition rate in case of similarly charged polyelectrolyte layer and colloid particles was negligible. Periodic variations in particle deposition rate correlated well with periodic changes in apparent zeta potential of the mica substrate covered by polyelectrolyte layers. These results suggested that in the case of PAH/PSS multilayers adsorbed from polyelectrolyte solutions of high concentrations there was little chain interpenetration between adjacent polyelectrolyte layers.