Statistical Mechanics of Polymer Systems

9530403自由的理论研究将继续开发计算聚合物熔体、混合物、嵌段共聚物、玻璃和液晶的热力学性质的理论。这种理论方法的一个主要和新颖的特点涉及单体分子结构、局部相关性和可压缩性的综合处理。首席研究人员将继续这项工作，将他的晶格团簇理论扩展到包括半柔性，以便描述聚合物玻璃和液晶。拟议研究的另一个方面将包括继续研究短链支化(和半柔性)对聚合物共混物(特别是聚烯烃共混物)的相容性的影响，以及在时间允许的情况下对其界面性质的影响。其他有待研究的现象包括聚合物共混物的相容性和玻璃化转变温度对压力的依赖关系。用含有复杂单体结构的模型准确描述聚合物共混物和聚合物液晶将需要包含来自远程关联的贡献，这些贡献只能借助复杂的基于计算机的组合算法来评估，该算法将被设计并应用于该项目。这项理论研究既涉及分析部分，也涉及计算部分。这项研究将使用首席研究员开发的形式主义来确定聚合物及其混合物的各种性质。将对这种形式主义进行修改，以模拟更现实的情况。***

9530403 Freed Theoretical research will continue on developing theories for calculating the thermodynamic properties of polymer melts, blends, block copolymers, glasses and liquid crystals. A main and novel feature of this theoretical approach involves the combined treatment of monomer molecular structures, local correlations, and compressibility. The principal investigator will continue this work by extending his lattice cluster theory to include semiflexibility in order to describe polymer glasses and liquid crystals. Another aspect of the proposed research will involve continued studies of the influence of short chain branching (and semiflexibility) on the miscibility of polymer blends (with special focus on polyolefin blends) and, if time permits, on their interfacial properties. Other phenomena to be studied include the pressure dependence of polymer blend miscibility and glass transition temperatures. The accurate description of polymer blends and of polymer liquid crystals with models containing complex monomer structures will require the inclusion of contributions from long range correlations, contributions that only can be evaluated with the aid of sophisticated computer-based combinatorial algorithms which will be devised and applied to this project. %%% This theoretical research involves both analytical and computational components. The research will determine a variety of properties of polymers and their mixtures using a formalism developed by the principal investigator. Modifications to this formalism will be made in order to model more realistic situations. ***