Poly(styrene) latex carrying cerium(IV)-initiated terminally attached cleavable chains: Analysis of grafted chains and model of the surface layer

Ce(IV)-initiated grafting of N(2-methoxyethyl-acrylamide) (MEA) to a shell of poly(styrene-co-2-hydroxyethyl acrylate) on polystyrene latex has been performed and the molecular weight distribution of the graft determined by size exclusion chromatography (SEC) on grafted chains cleaved from the surface. Cationic poly(styrene) beads were covered with a shell containing poly(styrene-co-2-hydroxyethyl acrylate) utilizing an azo initiator. The density of the surface hydroxyl groups was assessed by saponification of the ester bonds followed by conductometric titration of the resulting carboxylic residues. Ce(TV) redox initiation of MEA from the surface hydroxyl groups produced chains terminally attached to the latex surface. MEA consumption kinetics were monitored by HPLC of the supernatant on a reverse phase column. Competing solution polymerization of MEA occurred, probably due to leakage of shell copolymer from the beads. The terminally attached chains were characterized by quantitative SEC following cleavage from the surface by saponification, allowing a model of the tethered surface to be developed.