KINETICS OF TELECHELIC POLYMER-CHAIN BRIDGING AND TRANSPORT BETWEEN 2COLLOIDAL SURFACES

The present study is motivated by the following questions: (1) how do adsorbing telechelic polymer chains in a polymer brush transport to an approaching bare surface? (2) can polymer chains exchange between two approaching surfaces that are already fully covered by loopy brushes? We study chain transport between surfaces by dynamic light scattering using a mixture of 38 nm and 91 nm polystyrene (PS) particles so we c an monitor only the polymers adsorbed on the 91PS particles. We find t hat the chain transport or exchange can occur between a brush and a ba re surface or between two partially covered surfaces. In these cases e quilibration of chains can be attained. Chain bridging during Brownian encounters is essential for chain transport or exchange to occur. The refore chain exchange between two highly covered surfaces is not allow ed owing to the short encounter time. This inability of chains to exch ange and competitive adsorption between long and short chains result i n a non-equilibrium state where long and short chains can be selective ly adsorbed on different latex particles.