Segment Distributions in Lamellar Diblock Copolymers

Abstract

Predictions from a self-consistent-field theory of inhomogeneous polymer systems are compared to results obtained from neutron reflectivity studies of ordered lamellar diblock copolymers and their blends with homopolymers. Previously measured distributions of chain ends and junction points in neat diblock copolymers, and of homopolymers in diblock copolymer/homopolymer blends, were found to be in quantitative agreement with theory. By extending the theory to more strongly segregated systems, we show that relatively weak centralization of chain ends within the appropriate domain of a lamellar diblock copolymer is expected in all cases. Agreement between theoretical and experimental values for the interfacial widths between copolymer domains or between immiscible homopolymers is also quantitative, provided that the effects of fluctuations of the interface position are appropriately taken into account. © 1993, American Chemical Society. All rights reserved.