Thermally enhanced photoinduced in‐plane reorientation in photo‐cross‐linkable polymer liquid crystalline films and its application to linear polarizer |
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| Authors: | Nobuhiro Kawatsuki Ryoji Tsutsumi Akie Hiraiwa Hirofumi Takatsuka Takeya Sakai |
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| Institution: | 1. Department of Materials Science and Chemistry, Himeji Institute of Technology, University of Hyogo, 2167 Shosha Himeji, 671‐2201 Japan;2. Hayashi Telempu Co. Ltd., 100‐2 Machiyabora, Kamekubi, Toyota, 470‐0375 Japan |
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| Abstract: | Thermally enhanced photoinduced in‐plane molecular reorientation in new photo‐cross‐linkable polymer liquid crystalline (PPLC) films comprising 4‐ω‐(4‐methoxycinnamoyloxy)alkyloxy]biphenyl side groups is explored using linearly polarized ultraviolet (LPUV) light exposure and subsequent annealing. The influence of the alkylene spacer length between the photo‐cross‐linkable group and the biphenyl mesogenic moiety is investigated. The straight‐line characteristics of the photoreactive mesogenic side group and the 4‐methoxycinnamoyl group play important roles in the high photoreactivity and the large thermally enhanced molecular reorientation, where the in‐plane order and the birefringence of the reoriented film are 0.61 and 0.18 are obtained. Finally, cooperative molecular reorientation of dichroic dyes doped in PPLC films is also achieved to fabricate a linear polarizer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4712–4718, 2008 |
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| Keywords: | alignment birefringence irradiation linear polarizer liquid‐crystalline polymers (LCP) orientation photo‐cross‐linking photoinduced orientation photoreactive effects polymer liquid crystal thin films |
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