Synthesis, characterization and photoreaction of side-chain liquid-crystalline polymers comprising cinnamoyl biphenyl mesogen

• Published in: Macromolecular chemistry and physics Vol. 197; no. 6; pp. 1919 - 1935
• Main Authors: Kawatsuki, N, Sakashita, S, Takatani, K, Yamamoto, T, Sangen, O
• Format: Journal Article
• Language: English
• Published: BASEL Huthig & Wepf Verlag 01.06.1996
• Subjects: Physical Sciences; Polymer Science; Science & Technology; BEHAVIOR
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021970612

Liquid-crystalline (meth)acrylate monomers and polymers having mesogenic groups based on 4-alkyloxy-4'-cinnamoylbiphenyl (m = 2, 6) were synthesized. The methacrylate monomers 4c, d were polymerized by free radical polymerization. Under the same conditions, the acrylate monomers 4a, b gave unidentified polymers in very low yield. To synthesize the acrylate polymer, the acrylate monomer having 4-alkyloxy-4'-hydroxybiphenyl (m = 2, 6) was polymerized followed by the esterification of the hydroxy group using cinnamoyl chloride. All synthesized polymers having mesogenic moieties showed liquid-crystalline phases in the high temperature range between 140 degrees C and 245 degrees C. The difference of aggregation of the cinnamoyl biphenyl mesogen among the polymers was studied by UV-VIS spectroscopy at various temperatures. The photoreaction was performed in both solution and thin film. The [2+2] cycloaddition reaction preferentially occurred in the thin film although both [2+2] cycloaddition and photo-Fries reactions could occur in the solution.