Microphase Separation in Block Copolymers. Zeroth Approximation Including Surface Free Energies

Abstract

The conditions necessary for microphase separation in block copolymers containing an arbitrary number of blocks of two monomers, A and B, are developed as a function of block copolymer composition, molecular weight, number of blocks per molecule, and interaction parameter between the corresponding homopolymers. As the number of blocks increases in block copolymer samples of equal composition and molecular weight, it is predicted that microphase separation becomes more and more difficult, i.e., that it occurs at higher and higher values of the interaction parameter, χAB. The results of the present treatment are compared with the conditions for phase separations in mixtures of homopolymers. © 1970, American Chemical Society. All rights reserved.