Terminal–Terminal Types of Liquid Crystals. III. Thermal and Electrooptical Behavior of Liquid Crystalline Bis[urethane]s
作者:Kazuo Sugiyama、Koichi Kato、Kohei Shiraishi
DOI:10.1246/bcsj.65.2259
日期:1992.8
Novel terminal-terminal types of liquid crystalline bis[urethane]s 3, prepared from (S)-2-methylbutyl 4-[4-(11-hydroxyundecyloxy)benzylideneamino]cinnamate 2 and various diisocyanates, were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Bis[urethane]s 3c obtained from 1,3-diisocyanatobenzene and 3d from 2,4-diisocyanatotoluene exhibit a smectic state, while bis[urethane]s 3a obtained from 1,6-diisocyanatohexane, 3b from bis(4-isocyanatophenyl)methane and 3e from 2,6-diisocyanatotoluene show no mesophases. It was found from IR spectroscopic results that inter- and intramolecular hydrogen bondings due to N–H and C=O of urethane bonds play an important role in the formation of mesophase. The dual-frequency drive, based on light scattering driven by the application of an a.c. current at different frequencies, was studied in the smectic A state of 3c and 3d: τr at 0.1 Hz are 0.84 and 0.25 s, τr at 1 kHz are 9.75 and 8.95 s for 3c and 3d, respectively.
通过差示扫描量热法(DSC)和偏振光学显微镜(POM)研究了由 (S)-2- 甲基丁基 4-[4-(11-羟基十一烷氧基)亚苄基氨基]肉桂酸酯 2 和各种二异氰酸酯制备的新型液晶双[氨基甲酸乙酯]3 的端末类型。从 1,3-二异氰酸酯苯中得到的双[氨基甲酸乙酯]3c 和从 2,4-二异氰酸酯甲苯中得到的双[氨基甲酸乙酯]3d 显示出熔融状态,而从 1,6- 二异氰酸酯己烷中得到的双[氨基甲酸乙酯]3a、从双(4-异氰酸酯苯基)甲烷中得到的双[氨基甲酸乙酯]3b 和从 2,6- 二异氰酸酯甲苯中得到的双[氨基甲酸乙酯]3e 则没有显示出中间相。红外光谱结果表明,氨基甲酸酯键的 N-H 和 C=O 所产生的分子间和分子内氢键在介相的形成中起了重要作用。在 3c 和 3d 的 Smectic A 状态下,研究了基于不同频率交流电驱动光散射的双频驱动:0.1 Hz 时的 τr 分别为 0.84 秒和 0.25 秒,1 kHz 时的 τr 对 3c 和 3d 而言分别为 9.75 秒和 8.95 秒。