Complete and comprehensive orientation of cylindrical microdomains in a block copolymer sheet

Abstract

Significant progress in cylindrical microdomain orientation is reported for a polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene triblock copolymer (SEBS-16) as analyzed by two-dimensional small-Angle X-ray scattering. For this purpose, the morphological transition from sphere to cylinder was utilized. By applying compressional flow to the SEBS-16 specimen undergoing a morphological transition at 210 °C, superior cylinder orientation was achieved compared with the results obtained by applying the compressional flow to a cylindrical phase. The flow-Treated specimens were further subjected to subsequent thermal annealing at 210 °C. It was found that the cylinder orientation proceeded by the subsequent thermal annealing even for flow-Treated specimens with less oriented cylinders. Furthermore, the fraction of grains in which the plane of the hexagonal lattice of cylinders is oriented parallel to the specimen surface increased due to the subsequent thermal annealing, even for the specimen with the best cylinder orientation.