Enhancement in the orientation of the microdomain in block copolymer thin films upon the addition of homopolymer

Abstract

Cylindrical microdomains in thin films of mixtures of polystyrene-block-poly-(methyl methacrylate) and poly(methyl methacrylate) (PMMA) homopolymer are oriented normal to the film surface (see Figure). Confining the PMMA homopolymer to the microdomains increases the persistence of microdomain orientation over large distances; thus, aspect ratios up to similar to10 are achievable without the use of an external field.