Theoretical and Experimental Studies of Thermal Motions in Liquids and Polymer Systems

罗伯特·佩科拉教授得到了实验物理化学计划的资助，继续他对复杂液体系统中分子动力学的理论和实验研究。佩科拉教授正在研究聚合物材料、寡核苷酸和DNA限制片段的运动。未来三年复杂液体的主要研究领域包括：1)小棒状分子在溶液中的重新取向、平移和结构，包括与类似尺寸的溶剂分子和与聚合物材料的混合。特定的体系包括一系列同源双螺旋寡核苷酸的溶液，以及一系列棒状探针在无定形和玻璃状聚甲基丙烯酸甲酯中的运动。2)单链半刚性棒状高分子链的动力学，包括利用基因工程技术制备的一系列同源单分散DNA限制性片段的理论和实验研究。3)刚性和半刚性分子在非稀溶液中的运动，包括寡核苷酸、DNA限制片段和含有溶剂的三元溶液的研究，以及棒状大分子与线圈或包覆的二氧化硅球混合的研究。在这些实验中使用了广泛的实验技术，包括：瞬变电双折射、光散射、干涉测量、光子相关光谱和力瑞利散射。理论技术包括分析建模和计算机模拟。

Professor Robert Pecora is supported by a grant from The Experimental Physical Chemistry Program to continue his theoretical and experimental studies of the dynamics of molecules in complex liquid systems. Professor Pecora is studying the motions of polymeric materials, oligonucleotides, and DNA restriction fragments. The main areas of complex liquids to be studied over the next three year period include: 1) reorientation, translation,and structure of small rodlike molecules both in solution with similarly sized solvent molecules and mixed with polymeric materials. Particular systems include solutions of a homologous series of double helical oligonucleotides, and motion of a series of rodlike probes in amorphous and glassy polymethylmethacrolate. 2) dynamics of single semirigid rodlike polymer chains including theoretical and experimental studies of a homologous series of monodisperse DNA restriction fragments prepared using genetic engineering techniques. 3) motions of rigid and semirigid molecules in nondilute solutions including studies of oligonucleotides and DNA restriction fragments and ternary solutions containing solvent, and rodlike macromolecules mixed with either coils or coated silica spheres. A broad range of experimental techniques are used in these experiments including: transient electric birefringence, light scattering, interferometry, photon correlation spectroscopy, and force Rayleigh scattering. Theoretical techniques include both analytical modeling and computer simulations.