Ordered melts of block copolymers of ethylene oxide and 1,2-butylene oxide

An account is presented of recent work on specially synthesised diblock, tr iblock and cyclic block copolymers of ethylene oxide and 1,2-butylene oxide . Simultaneous small-angle X-ray scattering and differential scanning calor imetry have been used to investigate the effects of block architecture on t he stabilities and structures of microphase-separated melts. Stable lamella r, hexagonal, body-centred cubic and gyroid phases were detected. Phase dia grams are compared, one with another and with those predicted by the exact self-consistent mean-field theory, and centre-block stretching in lamellar phases is confirmed.