Research Initiation Awards: Screening Vs. Hydrogen Bondin in Chain Molecules

这一计划将把一个极其复杂的问题转化为两个更容易处理的问题，并提供初步结果，为未来的发展指明方向。当考虑缔合链与自身和溶剂相互作用的方式时，主要的复杂性是同一链上的原子相互筛选的方式与缔合点试图克服这种筛选的方式之间的耦合。考虑到链的长度、在链上的位置和链的灵活性，筛分本身是复杂的。氢键是复杂的，因为它的短程性质，取向依赖性，需要匹配施主和受体，以及形成环或多个分支的可能性。当这些现象同时发生时，就像在化学工程师、聚合物科学家和分子生物学家感兴趣的许多系统中一样，基于分子的描述方法可能变得过于繁琐和有限。为了将这种耦合分解为两个独立的组分，结合链分子的积分方程组理论，提出了具有方形势垒氢键中心的硬链分子的分子动力学计算机模拟。协调这两种互补的方法将为预测溶液粘度、链构象、聚合物共混混溶程度和地下水中有机污染物的溶解度等性质提供坚实的基础。

This program will convert an extremely complicated problem into two more tractable problems and provide initial results which point the way for future developments. The major complexity which develops when considering ways that associating chains interact with themselves and solvents is the coupling between the ways that atoms on the same chain screen each other vs. the ways association sites seek to overcome this screening. Screening by itself is complicated by considerations of chain length, position on the chain, and flexibility of the chain. Hydrogen bonding is complicated by its short-range nature, orientational dependence, the need to match donors with acceptors, and the possibilities of forming rings or multiple branches. When these phenomena occur together as in many systems of interest to chemical engineers, polymer scientists, and molecular biologists, approaches to a molecular-based description can become either too cumbersome too limited. To resolve this coupling into the two separate components, molecular dynamics computer simulations of hard chain molecules with square-well hydrogen bonding sites are proposed in conjunction with an integral equation theory of chain molecules. Coordinating these two complementary methods will provide a firm basis for making predictions of properties like solution viscosity, chain conformation, polymer blending miscibility, and solubilities of organic contaminants in groundwater.