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

The interaction between polystyrene-poly(ethylene oxide) (PS-PEO) dibl ock copolymers and PS latex particles in water is examined by both dyn amic 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 exp eriments establish that while the exchange rate of polymers among mice lles is slow, the adsorption and redistribution of block copolymers on to the latex surface occur essentially instantaneously upon mixing. Th e most unusual observation is a systematic decrease in the adsorbed la yer thickness for a series of latices with increased particle diameter . A kinetic model is presented to explain this result.