Stepwise polyelectrolyte assembly on particle surfaces: a novel approach to colloid design

Polyelectrolyte multilayers were deposited onto polystyrene and melamine formaldehyde latex particles by means of consecutive adsorption. Two different methods of multilayer growth were employed. First, adsorption of polyelectrolytes at a concentration exceeding saturation amounts was combined with the removal of the nonbound polyelectrolyte by means of centrifugation. Second, adsorption of polyelectrolyte was performed at a concentration just sufficient for saturation coverage. Both methods yielded continuous layer growth. The process of film formation was followed by electrophoresis, dynamic light scattering, single particle light scattering and fluorescence intensity measurements. Layer deposition onto partially crosslinked melamine resin latex particles, which were soluble at pH values of less than 1.6, resulted in the production of three-dimensional thin polyelectrolyte shells upon dissolving the core. The ultrathin shells were observed by means of scanning and transmission electron microscopy. © 1998 John Wiley & Sons, Ltd.