DIRECT ADSORPTION OF POLYSTYRENE POLY(ETHYLENE OXIDE) MICELLES IN WATER ONTO POLYSTYRENE LATEX-PARTICLES

The interaction between polystyrene-poly(ethylene oxide) (PS-PEO) diblock copolymers and PS latex particles in water is examined by both dynamic light scattering and size exclusion chromatography (SEC). The two block copolymer samples form micelles with core radii r(c) = 6 nm and total (hydrodynamic) radii of 26 and 30 nm, respectively. The SEC experiments establish that while the exchange rate of polymers among micelles is slow, the adsorption and redistribution of block copolymers onto the latex surface occur essentially instantaneously upon mixing. The most unusual observation is a systematic decrease in the adsorbed layer thickness for a series of latices with increased particle diameter. A kinetic model is presented to explain this result.