甲壳素类胆甾液晶的可控热致和电致变色效应研究

A large family of chitin liquid crystals, including more than 30 kinds of derivatives such as the series of hydroxyalkyl chitosan、aroyl and benzyl chitosan、acylated chitosan、carboxyalkyl chitosan、cyanoalkyl chitosan、alkyl chitosan and diacylated chitosan, was estabished. The influences of the structure factors such as molecular weight、degree of deacetylation、size of substituent、degree of substitution and position of substitution on the critical behaviors of lyotropic liquid crystals were investigated. The results supported scientific basis for the molecular design of synthesis for chitin liquid crystals . There were evident effects of additive small molecular electrolytes on the liquid crystallinity of these kinds of polyelectrolytes. Cyanoethylhydroxypropyl chitosan was found to have thermotropic liquid crystalline behavior. The pitch of cholesteric phase was researched by SEM and AFM plus the technique of oxidizing acid etching. The helicoidal properties of cholesteric order were studied by means of circular dichroism. The chirality of two levels, i.e. chiral chain conformation and twist cholesteric layers, in phthaloyl chitosan all reversed after the conditions such as concentration or solvent changes. The chirality transfer occured between two chiral levels. However the distribution of pitch was very wide, so no obvious thermochromatic or electro-chromatic effects were observed.

研究一类新的天然高分子胆甾液晶即甲壳素及其衍生物的选择光反射性质（主要包括热致变色效应和电致变色效应）。研究影响这两个效应的基本因素如链结构（包括取代基性质和位置、取代度、脱乙酰度和分子量等）、添加成分（电解质等）和溶剂，提出链构象持续长度与螺距的经验关系式，并用于指导合成的分子设计，控制液晶颜色及热致或电致变色范围。