MICELLIZATION AND GELATION OF BLOCK-COPOLY(OXYETHYLENE OXYBUTYLENE) IN AQUEOUS-SOLUTION

A series of diblock copolymers E30Bn, with n in the range 3 to 16, was prepared by sequential anionic polymerization, and the association be havior of the copolymers in aqueous solution was investigated, as was the gelation of their concentrated micellar solutions. At temperatures in the range 30-50-degrees-C, a minimum B-block length of four to fiv e units was required for micellization. Gelation of micellar solutions of the copolymers was observed for copolymers with B-block lengths of six to seven units or more. The relationships between (i) standard Gi bbs energy of micellization and molecular characteristics and (ii) cri tical gelation concentration and micellar characteristics were explore d.