Segment density distributions of homopolymers and diblock copolymers at the interface of immiscible homopolymers

Abstract

The use of neutron reflectivity to determine the segment density distributions of homopolymers and diblock copolymers at the interface between two immiscible homopolymers is discussed. We report on the interface formed between poly(styrene), PS, and poly(methyl methacrylate), PMMA, in the presence of symmetric diblock copolymers of PS and PMMA, denoted P(S-b-MMA). It is shown that the interface formed between PS and PMMA in the presence of P(S-b-MMA) is broader than that formed by the two homopolymers or that found in the bulk diblock copolymers. Significant penetration of the two homopolymers into the interfacial region is found. In addition, a self-consistent description of the segment density distribution of the two blocks of the P(S-b-MMA) at the interface is found.