Aqueous mesophases of block copolymers of ethylene oxide and 1,2-butylene oxide

Recent work on water-soluble block copolymers of ethylene oxide and 1,2-but ylene oxide is described. Small-angle X-ray and neutron scattering have bee n used to probe the structures of aqueous micellar mesophases, with particu lar attention paid to the effects of steady and oscillatory shear. Effects of temperature and concentration are described, and the relationship of cub ic structure (bcc or fcc) to diblock copolymer composition is explained in terms of the nature of the intermicellar potential. The rheology of the com plex fluids (so-called soft gels) outside the structured-mesophase (hard ge l) regions is discussed.