分子链构象变化对高分子液晶相行为的影响

EFFECT OF MOLECULAR CONFORMATION CHANGES ON THE\=PHASE BEHAVIOR OF LIQUID CRYSTALLINE POLYMERS

聚肽高分子溶解在含有机酸的有机溶剂中可以在室温条件下形成液晶．随着温度的下降，体系中的酸分子会引起聚肽分子链发生由刚性螺旋结构向柔性无规线团结构的构象转变．这种转变将导致一个由液晶态向非液晶态的相变．在Ｆｌｏｒｙ格子理论和ＺｉｍｍＢｒａｇｇ理论的基础上，作者已提出了有关这一现象的理论解释，并通过引入一个与温度有关的库恩链长径比ｘｋ，使理论进一步完善，更切实际地解释聚肽液晶的相行为．此外，还讨论了不同分子刚柔性，不同高分子溶剂作用系数χ对液晶相行为的影响，以及研究了聚肽液晶的有序参数．

In the presence of denaturing solvent,solutions of polypeptide can be liquid crystalline at room temperature.They may undergo an anisotropic\|isotropic transition at low temperatures where the intramolecular helix\|coil transformation occurs.On the basis of Florys lattice model and Zimm\|Bragg's notion for the helix\|coil transition,a theory considering the above phenomenon has been proposed.In this work,such theory was further developed by replacing the axial ratio x with the Kuhn chain axial ratio x\-k which is temperature\|dependent.The calculation results show that an improved agreement between the theory and the experimental data has been achieved,and an appreciable influence on the phase behavior from both chain rigidity and polymer\|solvent interaction parameter was found.Finally,the temperature effect on orientational parameter S was also studied.The information obtained through the investigation may find important applications, such as envisaging new routes for processing the rigid\|flexible block copolymer with better mechanical properties, and helping to understand bioprocesses in the life phenomena.\=