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本文通过存在于胆甾醇丁二酸单酯(MCB)和4—(4—烷氧基苯甲酰氧基)—4′—苯乙烯基吡啶(nSZ)间的氢键作用合成了一系列新的胆甾型液晶,其液晶行为通过DSC、偏光显徽镜及变温广角X光衍射等手段进行研究。对于nSZ:当n≤3时,仅呈现向列相;当n=4,5时,呈现近品A相和向列相;当n＝6,7时,还出现一种单变的近晶相(S相);当n≥8时,向列相不存在,只呈现近晶A相和单变的S_1相。MCB不是液晶,而两者的1:1复合物均呈现互变的近晶C相和胆甾相,并且当n≤3时,nSZ:MCB的相变区间比nSZ的相变区间宽。X光衍射结果表明,7SZ扣8SZ的层厚度(d值)比基分子全伸展理论长度要长,这意味着这种不含强极性基团(如硝基、氰基)的液晶分子呈双层排列。
In this paper, we have synthesized a series of new hydrogen bonds through the hydrogen bonding between cholesteryl succinate (MCB) and 4- (4-alkoxybenzoyloxy) -4’-styrylpyridine Of the cholesteric liquid crystal, the liquid crystal behavior through the DSC, Polaroid microscope and variable temperature wide-angle X-ray diffraction and other means of study. For nSZ: when n≤3, only the nematic phase is present; when n = 4, 5, the near-product A phase and the nematic phase are present; when n = 6,7, a singular smectic Phase (S phase); when n≥8, the nematic phase does not exist, only showing the smectic A phase and the single S_1 phase. The MCB is not a liquid crystal, and the 1: 1 complexes of both exhibit intermixing smectic C and cholesteric phases, and when n ≦ 3, the nSZ: MCB has a wider phase transition than the nSZ. X-ray diffraction results show that the layer thickness (d value) of 7SZ buckle 8SZ is longer than the theoretical length of full extension of the base molecule, which means that the liquid crystal molecules without such strong polar groups (such as nitro group and cyano group) Double arrangement.