Effects of block architecture and composition on the association properties of poly(oxyalkylene) copolymers in aqueous solution

A block copolymer of hydrophilic poly(ethylene oxide) and a hydrophobic pol y(alkylene oxide) can associate in dilute aqueous solution to form micelles . The results of recent investigations of the micellisation behaviour and m icelle properties of such copolymers are described. Copolymers of ethylene oxide with propylene oxide, 1,2-butylene oxide or styrene oxide are conside red, including aspects of their preparation. Experimental methods for deter mination of critical conditions for micellisation, micelle association numb er and spherical-micelle radius are summarised. Effects of temperature, com position, block length and block architecture (diblock, triblock and cyclic -diblock) are described and, where possible, related to the predictions of theory. Brief consideration is given to the dynamics of micelle formation/d issociation, to cylindrical micelles, and to effects of added salts.