title: Free Surface Command Layer for Photoswitchable Out-of-Plane Alignment Control in Liquid Crystalline Polymer Films.
abstract: To date, reversible alignment controls of liquid crystalline materials have widely been achieved by photoreactive layers on solid substrates. In contrast, this work demonstrates the reversible out-of-plane photocontrols of liquid crystalline polymer films by using a photoresponsive skin layer existing at the free surface. A polymethacrylate containing a cyanobiphenyl side-chain mesogen adopts the planar orientation. Upon blending a small amount of azobenzene-containing side-chain polymer followed by successive annealing, segregation of the azobenzene polymer at the free surface occurs and induces a planar to homeotropic orientation transition of cyanobiphenyl mesogens underneath. By irradiation with UV light, the mesogen orientation turns into the planar orientation. The orientation reverts to the homeotropic state upon visible light irradiation or thermally, and such cyclic processes can be repeated many times. On the basis of this principle, erasable optical patterning is performed by irradiating UV light through a photomask.
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering and ‡Nagoya University Venture Business Laboratory, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakai
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering and ‡Nagoya University Venture Business Laboratory, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tanaka
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering and ‡Nagoya University Venture Business Laboratory, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Hara
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering and ‡Nagoya University Venture Business Laboratory, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Shusaku
authors.initials: S
authors.lastname: Nagano
authors.affiliation: Department of Molecular Design and Engineering, Graduate School of Engineering and ‡Nagoya University Venture Business Laboratory, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Seki