Conformation and Dynamics of Chain Molecules: Molecular Studies on Correlation between Structure and Properties in Condensed Systems

本研究项目涉及以下四个主要方面。在第一门课《溶液中的孤链与分子间相互作用》中，我们发展了螺旋蠕虫链理论，并对一些刚性链体系进行了实验验证。对Rheta溶液中第三个病毒系数的精确测量提出了一个新的Rheta条件概念，这一概念无法用现有的“双参数理论”来解释。给出了钙调素和蛋清蛋白构象的新图片。在“均相体系的动力学和构象行为”的第二个主题中，讨论了重复的拓扑基础、局部运动的“齿轮模型”、DNA的脉冲凝胶电泳法和棒状分子剪切溶液的稳定性。给出了棒状聚合物、聚电解质溶液、聚合物/聚合物/溶剂体系、嵌段共聚物胶束扩散和微分粘弹性的实验结果。综述了中子散射和荧光退极化技术揭示的聚合物的局部链段运动，嵌段共聚物的密度泛函理论以及剪切场作用下聚合物共混物的相行为。在“临界现象、相行为与界面现象”的第三个专题中，报道了各种体系的相变、螺旋-球状相变、平行板之间的链构象和界面上的聚合物链的实验和理论结果。最后，在第四类“理论分析与模拟”中，讨论了生物进化中的UCST行为理论、溶胶-凝胶转变理论和渗流理论。

This research project concerns with the following four major areas. In the first subject on "isolated chain and intermolecular interaction in solution," the theory of helical worm-like chain was developed and examined through experiments on some stiff chain systems. Precise measurements of the third viral coefficients in rheta solution suggested a new concept of the rheta condition that cannot be explained by the existing "two parameter theory." New pictures on the conformation of calmodulin and egg-white alubumin were presented. In the second subject on "dynamics and conformational behavior of homogeneous systems, "a topological foundation" of repetition, "a gear-model" on local motion, "pulse gel electrophoresis of DNA" and "stability of sheared solution of rodlike molecules" were discussed. Experimental results on rodlike polymers, polyelectrolyte solution, polymer/polymer/solvent systems, diffusion of block coplymer micelles and differential viscoelasticity were presented. Reviews were given on local segmental motions of polymers revealed by neutron scattering and fluoresence depolarization techniques, and also on a density functional theory of block copolymers and on phase behavior of polymer blends under shear field. In the third subject on "critical phenomena, phase behavior and interfacial phenomena" experimental and theoretical results on phase transition in various systems, coil-globule transition, chain conformation between parallel plates and polymer chain on the interface were reported. Finally, in the forth category on "theoretical analysis and simulation," theories on UCST behavior, sol-gel transition and percolation theory on biological evolution were discussed.