Preparation of novel acrylate-based liquid crystalline polymers and the photoinduced alignment behavior of their films

• Published in: Journal of applied polymer science 2006-12, Vol.102 (5), p.4565-4572
• Main Authors: Zhu, Jun, Wu, Li-Ping, Zhang, Yu-Ying, Jin, Xi, He, Shang-Jin, Shi, Ke-Yu, Guo, XianZhi, Du, Zong-Jie, Zhang, Bao-Long
• Format: Article
• Language: English
• Subjects: Applied sciences; cyclopolymerization; Exact sciences and technology; liquid-crystalline polymers; Organic polymers; photoalignment; Physicochemistry of polymers; Polymers with particular structures; POM; Preparation, kinetics, thermodynamics, mechanism and catalysts
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.24985

Two acrylate monomers containing both mesogenic biphenyl group and photoreactive cinnamoyl group as well as different length of flexible spacers (i.e., n‐[4′‐(n‐cinnamoyloxyalkoxy)biphenyl‐4‐yloxy]alkyl acrylate, n = 4 (A4OO4C) and 6 (A6OO6C)) were synthesized for the first time. Their corresponding polymers (i.e., PA4OO4C and PA6OO6C) were obtained by free radical polymerization using AIBN as an initiator. The monomer A4OO4C showed smectic liquid crystalline phase and a clear fan texture was observed under optical polarizing microscope. However, no liquid crystalline phase was found for A6OO6C. In contrast, PA4OO4C showed no liquid crystalline phase while PA6OO6C showed a clear nematic schlieren texture during the cooling process. The optical polarized microscope of E5 cast on the top of the polymer film also showed the alignment. Furthermore, the irradiation of the polymer films by LP‐UV light led to the cycloaddition of the cinnamoyl groups, resulting in the simultaneous alignment of the biphenyl groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4565–4572, 2006