MICROPHASE SEPARATION IN BLOCK-COPOLYMERS

Block copolymers have been the focus of intense scientific and commerc ial development because of their ability to organize into precise stru ctures on the scale of ten to one hundred nanometers. The wide variety of morphologies exhibited by linear block copolymers made from two ch emically distinct monomers has been extensively studied over many year s and is now fairly well understood. Three extensions of these studies have uncovered new classes of structures and new relations between co polymer composition and morphology. These include block copolymers wit h a nonlinear chain architecture, linear terpolymers with three chemic ally different blocks, and mixtures of linear diblocks with molecular weight or compositional differences. These results have greatly expand ed the range of domain sizes and types of morphology that can be found in block copolymer materials.