Cylindrical domains of block copolymers developed via ordering under moving temperature gradient

Mita, Kazuki*; Tanaka, Hirokazu*; Saijo, Kenji*; Takenaka, Mikihito*; Hashimoto, Takeji

A zone heating method, which imposes the moving temperature-gradient field on order in process of various melts in general, enabled to control a macroscopic orientation of microdomain structures in block copolymer bulk. We applied the method to a polystyrene-block-polyisoprene diblock copolymer forming hexagonally packed cylindrical domains (hex-cyl) in the absence of extermal fields. We discovered that the method creates the following special texture of hex-cyl; (1) The texture seemingly consists of volume-filled columnar grains with the grain axis parallel to the temperature gradient axis (defined as the oz axis). (2) The cylinder axis always orients perpendicular to the oz axis with a rotational angle of the cylinder axis around the oz axis being fixed within a grain.