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

Shoichi Kubo, Sho Kobayashi, Shingo Hadano, Motonori Komura, Tomokazu Iyoda, Masaru Nakagawa

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

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 microphaseseparated 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.

Original languageEnglish
Article number06JC04
JournalJapanese Journal of Applied Physics
Volume53
Issue number6 SPEC. ISSUE
DOIs
Publication statusPublished - 2014 Jun

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