Studies of Thermal Motions in Liquids and Polymer Systems

罗伯特·佩科拉得到了理论和计算化学计划的资助，继续他的研究，涉及液体和聚合物系统中的运动。使用了各种光散射技术，例如法布里-珀罗涉术和光相关光谱，以及总强度光散射和瞬时电双折射衰减。我们将研究刚性和半刚性棒状分子的稀溶液和非稀溶液的动力学，这些分子包括多肽、胶原、小棒状蛋白、寡核苷酸和DNA片段。我们将研究相互作用和纠缠的影响，并阐明慢模的本质。研制了一种由包覆的二氧化硅小球和浸泡在溶剂中的刚性聚合物组成的模型复合液。该系统还将通过动态光散射和瞬变电双折射衰减进行研究。复合液体是一类普遍存在的含有聚合物、颗粒和溶剂的材料。它们被用作陶瓷前驱体、润滑剂、油漆和涂料、粘合剂以及色谱柱。由于它们的复杂性和缺乏适当的模型系统，这些系统中的物种之间的相互作用还没有得到很好的了解。Pecora已经构建了一种棒状/球状复合液体模型，它的动力学可以使用一种称为动态光散射的实验技术在棒状和球状两种成分的广泛范围内进行研究。

Robert Pecora is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research involving motions in liquid and polymer systems. A variety of light scattering techniques are used such as Fabry-Perot interferometry and photocorrelation spectroscopy as well as total intensity light scattering and transient electric birefringence decay. The dynamics of both dilute and nondilute solutions of rigid and semirigid rodlike molecules including polypeptides, collagen, small rodlike protein, oligonucleotides, and DNA fragments will be studied. The effect of interaction and entanglement will be investigated, and the nature of slow modes will be elucidated. A model composite liquid has been developed which consists of small coated silica spheres and a rigid polymer immersed in a solvent. This system will also be studied by dynamic light scattering and transient electric birefringence decay. Composite liquids are a ubiquitous class of materials which contain polymer, particles and solvent. They are used as ceramic precursors, lubricants, paints and coatings, adhesives, and in chromatographic columns. Due to their complexity and the lack of adequate model systems, the interactions between the species in such systems are not well understood. Pecora has constructed a model rod/sphere composite liquid whose dynamics can be studied over a wide range of composition of both the rods and the spheres using an experimental technique known as dynamic light scattering.