Photoalignment of Vertically Oriented Microphase Separated Lamellae in LC-LC Diblock Copolymer Thin Film.
The microphase separation and photoalignment behavior of a diblock copolymer consisting of two kinds of side chain liquid crystalline (LC) polymers are investigated. Here, the mesogens of photoresponsive azobenzene and non-photoresponsive cyanobiphenyl are introduced in the side chains. The azobenzene and cyanobiphenyl mesogens orient homeotropically and planarly, respectively, in a thin film state. The combination of these contrasting orienting properties leads to a formation of vertically oriented lamella in the microphase separation structure. Irradiation with linearly polarized light onto this polymer film induces a highly oriented microphase separation structure having regularly elongated stripe morphology with 30 nm periodicity. The nearly defect-free morphology of this LC-LC diblock copolymer after the photoalignment is a distinct feature when compared with those of coil (amorphous)-LC diblock copolymer films possessing the same azobenzene side chain.
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
Koichiro
K
Beppu
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
Yuki
Y
Nagashima
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
Mituo
M
Hara
Nagoya University Venture Business Laboratory, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
Shusaku
S
Nagano
Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan.
Takahiro
T
Seki
D001391:Azo Compounds / Q000737:chemistry; D002853:Chromatography, Liquid; D008027:Light; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties
D001391:Azo Compounds; D011108:Polymers; C009850:azobenzene
azobenzene; block copolymers; liquid crystalline polymers; photoalignment; vertical lamella