Directed self-assembly of nematic liquid crystalline polymers on a rubbed polyimide alignment layer

作者：Kubo Shoichi^*; Kobayashi Sho; Hadano Shingo; Komura Motonori; Iyoda Tomokazu; Nakagawa Masaru

来源：Japanese Journal of Applied Physics, 2014, 53(6): 06JC04.

DOI：10.7567/JJAP.53.06JC04

Amphiphilic diblock copolymers PEO-b-PMA(4OPB) comprising hydrophilic poly(ethylene oxide) (PEO) and hydrophobic nematic liquid crystalline polymethacrylate [PMA(4OPB)] subunits were synthesized by atom transfer radical polymerization. The liquid crystalline property and microphase-separated structure were investigated by differential scanning calorimetry, polarized optical microscopy, atomic force microscopy, and X-ray diffraction analysis. Unimodal PEO-b-PMA(4OPB) with 114 ethylene oxide repeating units and phenylbenzoate moieties as methacrylate side chain mesogens showed a nematic phase when the methacrylate repeating unit was around 57. Hexagonal cylinders of the PEO subunits were formed in nematic phase and supercooling states. The thin film on a rubbed polyimide alignment layer showed a microphase-separated structure independent of the rubbing direction, while horizontally aligned cylinders were observed in the presence of small nematic liquid crystalline molecules of 4-cyano-4'-pentyloxybiphenyl (5OCB). The assistance of nematic liquid crystalline molecules was necessary for directed self-assembly of the nematic liquid crystalline diblock copolymer in accordance with the rubbing direction of the polyimide alignment layer.

• 出版日期2014-6