Effects of hyperbranched prepolymers prepared from butyl acrylate and butyl methacrylate on the electro‐optical properties of polymer dispersed liquid crystal |
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Authors: | Zhigang Yang Ding Li Cuihong Pan Yinghan Wang |
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Institution: | State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, , Chengdu, 610065 China |
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Abstract: | Two hyperbranched prepolymers were synthesized via the reversible addition‐fragmentation chain transfer copolymerization of butyl acrylate or butyl methacrylate with divinyl benzene, respectively. These prepolymers were used in the photopolymerization‐induced phase separation process of preparing polymer dispersed liquid crystal (PDLC) films with no risk of gelation. The morphologies of PDLC samples were investigated. Of particular interest was that the driving voltage (V90) of PDLC with high glass transition temperature (Tg) matrix was as low as 5 V, whereas the V90 of PDLC with low Tg matrix was still high. An explanation for this phenomenon is the hypothesis that different interaction modes function at the interface of liquid crystal and polymer. Meanwhile, the hysteresis of the two systems was minor, which correlated with the hyperbranched structure of polymer. The on‐state transmittance (TON) of PDLC films enhanced because of the well matching between the refractive index of polymer and that of liquid crystal. Copyright © 2011 John Wiley & Sons, Ltd. |
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Keywords: | hyperbranched prepolymers reversible addition‐fragmentation chain transfer (RAFT) glass transition temperature (Tg) driving voltage (V90) hysteresis |
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