“Aggregation in Block Copolymer Solutions”

ABSTRACTThe ability to produce block copolymers has led to new materials with unique properties. The chemical connectivity of incompatible blocks forces segregation to occur at distances of the order of the block sizes. In block copolymer melts, the segregated domains form periodic ordered structures called microphases. Most block copolymers are strongly incompatible. In such cases, in order to ensure equilibrium microphase separated samples, the microphases are prepared from solution. Microphase separation in semidilute solutions of block copolymers in nonselective good solvent is analyzed. The solvent effects on the thermodynamics in the weak segregation limit are discussed. The concentration of block copolymer at the transition in good solvents, scales as φtN−.62and in ϑ solvents as N−.5. The transitions between microphase morphologies as a function of block copolymer concentration are studied.