Cyano terminated tolane compounds for polymer dispersed liquid crystal application: relationship between cyano terminated tolane based molecular structures and electro-optical properties |
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Authors: | Huimin Zhang Mei Chen Tianmeng Jiang Haiguang Chen Dechao Zhang Yunfeng Sun |
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Institution: | 1. Department of materials, University of Science and Technology Beijing, Beijing, P. R. China;2. Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, P. R. China;3. Beijing Bayi Space Liquid Crystal Material Technology Company, Beijing Key Laboratory of Liquid Crystal Materials Analysis and Application Technology, Beijing, P. R. China;4. Yantai Xianhua Chemical Technology Company, Yantai, P. R. China |
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Abstract: | ABSTRACTThe structures of the liquid crystal (LC) molecules have a key role in impacting the electro-optical performance of a polymer dispersed liquid crystal (PDLC) film. In this paper, the relationship between the LC molecular structures and the electro-optical properties of PDLC films is investigated based on an unexplored cyano-terminated tolane compounds (CTTCs) doped E8 LCs/UV polymers system. Due to the high polarity of CTTCs, LCs doped with the cyano-terminated tolane (CTT) molecules exhibit high birefringence and large positive dielectric anisotropy. On the whole, PDLC films doped with the CTT molecules exhibit a lower driving voltage than that doped with the pure E8. More excitingly, PDLC films based on CTT molecules with larger length-to-width ratio and longer conjugated system show higher contrast ratio (CR) and faster response time. Eventually, the mechanism of the effects of CTT-based molecular structures and the relationship between the electro-optical performance of PDLC films and CTT molecules are illustrated. This work paves a new way for optimising the electro-optical properties of PDLC films. |
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Keywords: | Cyano-terminated tolane liquid crystal high birefringence high positive dielectric anisotropy polymer dispersed liquid crystal electro-optical properties |
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