氢键缔合主链超分子液晶聚合物:间隔基及扩展介晶元长度的影响研究  

Hydrogen-bonding Associated Main-chain Supramolecular Liquid-crystalline Polymers: Influence of Variant Spacers and Rigid Cores

作　　者：岳力挽[1,2] 张淑静[1] 吴斌[1] 陆正宇[1] 方江邻[2] 谌东中[1] 

机构地区：[1]南京大学化学化工学院高分子科学与工程系介观化学教育部重点实验室,南京210093 [2]南京大学现代分析中心,南京210093

出　　处：《化学学报》2010年第4期351-357,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20874044;20004005)资助项目

摘　　要：采用慢挥发溶剂组装方法制备了一系列羧酸/吡啶氢键缔合的主链型超分子复合物,并采用FTIR,DSC以及偏光显微镜等对其相转变与热致液晶相行为进行了比较研究.研究表明,分别具有较短的6或10个亚甲基的烷烃间隔基的双苯甲酸衍生物4',4''-二羧酸-1,6-二酚氧基己烷(C6-2COOH)和4',4''-二羧酸-1,10-二酚氧基癸烷(C10-2COOH)的系列复合物具有较高的熔点和清亮点,一般都只出现结晶近晶相和多晶型转变现象.而具有柔顺性较好的四甘醇醚链间隔基的4,4'-二羧酸-α,ω-二酚氧基四甘醇醚(C8O4-2COOH)得到的系列复合物均在降温过程生成单致的流体近晶SA和/或向列N液晶相.可见,间隔基增长,相转变温度降低,最终导致真正的流体液晶相的产生.另一方面,对于从同一种二元羧酸得到的组装体系,从4,4'-联吡啶(4,4'-BPy)、4,4'-联吡啶乙烯撑(4,4'-BPyE)到对苯二酚二异烟酸酯(p-PhBPy),由于双键或酯基的引入,可变形性和极性增大,刚性依次减弱,尽管中心核部分持续长度增大,所得复合物的各向同性化温度降低,形成流体液晶相的趋势增强,液晶有序性降低,流动性增加.指出了早期文献报道的一些不一致甚至矛盾的结果.通过不同系列的对比研究,得出的一些规律性对氢键组装尤其对羧基/吡啶氢键缔合超分子体系设计与构筑具有一定指导意义.A series of hydrogen-bonding associated main-chain complexes based on dipyridyl and dicarboxylic acid derivatives have been prepared by slow solvent evaporation,and a comparative investigation has been conducted on their thermotropic phase transitions and liquid crystalline （LC） behavior by FTIR,DSC and polarized optical microscopy. All the complex series based on 4＇,4＇＇-dicarboxy-1,6-diphenoxyhex-ane （C6-2COOH） and 4＇,4＇＇-dicarboxy-1,10-diphenoxydecane （C10-2COOH） possessed higher melting and clearing points,usually showed soft crystal or crystalline smectic phases and crystal polymorphs except C10-2COOH/p-PhBPy complex displaying also an enantiotropic nematic phase,while the complexes based on 4,4＇-dicarboxy-α,ω-diphenoxy tetraethyleneglycol ether （C8O4-2COOH） with a longer flexible spacer exhibited monotropic fluidic smectic SmA and/or nematic phases. On the other hand,for those complexes based on such variant dipyridyls as 4,4＇-bipyridine （4,4＇-BPy）,trans-1,2-bis-（4-pyridyl）ethene （4,4＇-BPyE） and bis-isonicotinic ester of hydroquinone （p-PhBPy） with the same dicarboxylic acid,the LC order decreased and the fluidity increased accordingly. This kind of phase transition behavior could be mainly ascribed to the decrease in rigidity and increase in deformability and polarity from 4,4＇-BPy to 4,4＇-BPyE then to p-PhBPy. Furthermore,some discrepancies in earlier literature have been pointed out and our results may provide guidance for hydrogen-bonding association,in particular for the design and assembly of supramolecular polymers based on carboxylic acid/pyridyl pairs.

关 键 词：液晶 超分子聚合物 羧基-吡啶氢键缔合 流体近晶相 向列相 

分 类 号：O753.2[理学—晶体学]