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

Robert Pecora教授获得了实验物理化学计划的资助，继续他在复杂液体系统中分子动力学的理论和实验研究。皮科拉教授正在研究高分子材料、寡核苷酸和DNA限制性片段的运动。未来三年复杂液体研究的主要领域包括：1)小棒状分子在溶液中与类似大小的溶剂分子和与聚合物材料混合时的重定向、平移和结构。特定的系统包括同源系列双螺旋寡核苷酸的溶液，以及在无定形和玻璃状聚甲基丙烯酸甲酯中运动的一系列棒状探针。2)半刚性棒状聚合物链动力学，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，包括寡核苷酸和DNA限制性片段的研究，含溶剂的三元溶液，以及与线圈或涂覆二氧化硅球混合的棒状大分子。在这些实验中使用了广泛的实验技术，包括：瞬态电双折射、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.