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