Changes in Grain Structures Upon Blending of a Homopolymer to a Liquid-Crystalline Diblock Copolymer Which Forms Perpendicularly-Oriented Cylinders

We report on changes in grain structures upon blending of a homopolymer to a liquid-crystalline diblock copolymer which forms perpendicularly-oriented cylinders, as revealed by atomic-force microscopy (AFM). Image analyses of the AFM images have been conducted to identify grains in which the perpendicularly-oriented cylinders are uniformly ordered in a hexagonal lattice. As a result, it was found that the grains became smaller upon blending of a homopolymer. Furthermore, the grains which originally contacted to each other became isolated and were surrounded by a matrix where the perpendicularly-oriented cylinders are not regularly ordered. The degradation of the hexagonal order is due to the addition of too much homopolymer.