Design of holographic polymer‐dispersed liquid crystals based on solubility parameters |
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| Authors: | Eun Hee Kim Ju Yeon Woo Yeong Hee Cho Byung Kyu Kim |
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| Affiliation: | 1. Department of Polymer Science and Engineering, Pusan National University, Busan 609‐735, Republic of Korea;2. Graduate School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Asahidai, Tatsunokuchi, Ishikawa 923‐1292, Japan |
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| Abstract: | BACKGROUND: A slight change of polymer structure leads to a significantly different solubility parameter (SP), which is related to incompatibility and interface anchoring energy between a polymer and a liquid crystal (LC). RESULTS: Holographic gratings in polymer‐dispersed liquid crystals have been fabricated based on various urethane acrylate oligomer sizes and type of reactive diluent at two LC loadings. A large SP gap, using N‐vinylpyrrolidone as reactive diluent, gave much faster saturation of diffraction efficiency at higher level, but the grating failed to operate. On the contrary, films having a small SP gap, using 2‐ethylhexyl acrylate, operated under 20 V with a response time of about 10 ms, although their saturation of diffraction efficiency was relatively low. The results were interpreted in terms of morphology (determined using scanning electron microscopy), anchoring energy and resin elasticity. CONCLUSION: Low driving voltage and high diffraction efficiency are obtained by controlling the SP gap between LC and polymer. Copyright © 2007 Society of Chemical Industry |
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| Keywords: | anchoring energy elasticity holographic diffraction grating incompatibility |
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