Supercritical Fluids: Tunable Media for Chemical Reactions and Materials Processing

弗吉尼亚大学的Sergei Egorov得到了理论和计算化学项目的支持，致力于超临界流体及其作为化学反应和材料处理的可调介质的研究。该项目涉及超临界二氧化碳流体中二嵌段共聚物（如部分氟化烷烃链）的理论和计算模拟。二嵌段共聚物被建模为可能表现出键弯曲或扭转畸变的氟化和氢化单元链。非键单位通过伦纳德琼斯势相互作用。流体是通过将二氧化碳分子视为通过库仑和伦纳德-琼斯势与邻居相互作用的三个部分电荷来建模的。要建模的具体现象包括密度诱导的胶束聚集体的形成和解体，空间稳定纳米粒子的统计力学处理以及超临界流体中离子迁移率的研究。长期的兴趣是了解如何将环境友好的超临界流体用于化学和材料处理。该项目旨在了解如何用环保、无毒、不易燃、丰富且廉价的超临界溶剂（如二氧化碳）取代目前在化学工业中使用的传统液体溶剂。这项工作将通过开发和实施新的理论和计算方法，在分子水平上理解超临界流体的结构和动力学。活动包括对学生进行纳米材料加工方面的培训，并为他们进入工业界做好准备。

Sergei Egorov, at the University of Virginia, is supported by the Theoretical and Computational Chemistry Program to pursue research in supercritical fluids and their uses as a tunable media for chemical reactions and materials processing. The project deals with the theoretical and computational simulation of diblock copolymers, such as partially fluorinated alkane chains, in a supercritical carbon dioxide fluid. The diblock copolymer is modeled as a chain of fluorinated and hydrogenated units which may exhibit bond bending or torsional distortions. Nonbonded units interact via Lennard Jones potentials. The fluid is modeled by treating the carbon dioxide molecule as three partial charges interacting with neighbors via coulomb and Lennard-Jones potentials. Specific phenomena to be modeled include density-induced formation and disintegration of micellar aggregates, a statistical mechanical treatment of sterically stabilized nanoparticles and the study of ionic mobility in supercritical fluids. Long-term interest is in understanding how environmentally friendly supercritical fluids may be used for chemical and materials processing.This project deals with understanding how to replace conventional liquid solvents, currently used in the chemical industry, with environmentally friendly nontoxic, nonflammable, abundant and cheap supercritical solvents such as carbon dioxide. The work will proceed by understanding the structure and dynamics of supercritical fluids at the molecular level by the development and implementation of new theoretical and computational methods. Activity includes training of students in nanoscale materials processing and preparing them for entry into industry.