Molecular Thermodynamics of Fluids in Porous Materials

项目摘要 CTS-9700999蒙森，P.A. 联合马萨诸塞州阿默斯特 这一建议寻求支持的研究中的两个重要方面的多孔材料中的流体行为的分子建模。 两者都涉及吸附剂微观结构的作用。 传统上，这是根据单个孔隙中流体的行为来分析的。 虽然这一分析导致了重要的见解的问题，最近的研究，在这个小组和其他人已经表明，重要的影响发生，不能理解的基础上的单一孔隙行为。 与约束，润湿和吸附剂无序相关的影响都是重要的，在确定的行为和这些影响耦合。 计划使用计算机模拟和理论的研究方案。 其中要探讨的问题是：扩大范围的吸附剂的微观结构考虑;分析滞后回线的吸附/解吸等温线;进一步发展和应用的理论技术;和调查的流体混合物相分离在这样的系统。 第二个研究领域涉及吸附过程中吸收剂微观结构中结构变形的作用。 在几乎所有物理吸附的热力学处理中，都假定吸附剂是一种刚性基质，在吸附时结构不会改变。 虽然这是一个很好的近似在大多数情况下，现在有重要的例子，实验提供的证据显着的结构变形吸附。 提出了一个用蒙特卡罗计算机模拟研究这些现象的程序。 我们的目标是评估不同的模型吸附剂的灵活性，开发方法计算所需的热力学性质的研究在这样的系统中的相变和发展的见解时，这种结构变形可能会对系统产生重大影响。

PROJECT SUMMARY CTS-9700999 Monson, P.A. U. Massachusetts Amherst This proposal seeks support for research in the molecular modeling of two important aspects of fluid behavior in porous materials. Both concern the role of the adsorbent microstructure. Traditionally this has been analyzed in terms of the behavior of fluid in single pores. Although this analysis has led to important insights into the problem, recent research in this group and others has shown that important effects occur which cannot be understood on the basis of single pore behavior. Effects associated with confinement, wetting and adsorbent disorder are all significant in determining the behavior and these effects are coupled. A program of research using computer simulation and theory is planned. Among the issues to be explored are: extending the range of adsorbent microstructures considered; analysis of hysteresis loops in adsorption/desorption isotherms; further development and application of theoretical techniques; and investigation of fluid mixture phase separation in such systems. The second area for study involves the role of structural deformations in the absorbent microstructure during adsorption. In almost all thermodynamic treatments of physical adsorption it has been assumed that the adsorbent is a rigid matrix that is not structurally altered upon adsorption. While this is an excellent approximation in most circumstances there are now important examples where experiments provide evidence of significant structural deformations on adsorption. A program to study these phenomena using Monte Carlo computer simulation is suggested. The goals are to evaluate different models for adsorbent flexibility, develop methods for calculating the thermodynamic properties needed for a study of phase transitions in such systems and to develop insights into when such structural deformation may have a significant impact on the system.