Gas Adsorption in Nanoporous Materials: Molecular Structure and Recognition

lee， Lloyd L/ U of Oklahoma的纳米结构材料目前正在开发用于分子吸附和分子识别。在商业应用中，传感器材料的设计和选择[65,66]大多是通过试错和定性思维来完成的，而不是根据量身定制的特异性和定量原则。随着纳米结构材料的发展，如自组装单层（sam）和树枝状结构，已经创造了大量的化学和物理性质供选择。我们需要在分子水平上理解分子相互作用的本质和后果。本研究旨在利用分子理论和计算机模拟，建立气凝胶、沸石和星爆树状大分子三种典型纳米材料中气体吸附的微观框架。这提供了一个根植于分子水平的定量原理，将有助于气体吸附和分子识别设备的设计和开发。从广义上讲，有较旧的纳米材料（如沸石、膜、气凝胶、活性炭等）和较新的纳米材料（如星形聚合物、树突状聚合物等）。这些底物中包含的气体（流体）在分子分布、等等吸附热、相行为、热力学性质、吸附等温线、分离效率（对于混合物）、选择性吸附和分配系数方面发生了什么变化？需要精确的分子理论和有针对性的分子模拟来给出有序底物周围密闭气体分布的概率密度，以及它们与热力学性质的理论联系。这正是我们统计吸附力学的任务。首席研究员将开发一种新的积分方程（IE）理论，并进行分子计算机模拟，以确定纳米结构周围夹杂气体和气体混合物的气体结构（分布函数）和热力学性质。他使用现有的复制Ornsterin-Zernike （ROZ）方程作为起点。在随机介质和规则介质中，在刚性吸附剂和可变形吸附剂中，将发展新的夹杂气体形式。传统的ROZ只能处理刚体矩阵。他使用双温度淬火程序来建立响应系统的新方程。此外，通过设计满足一组精确自洽原则的新的闭包关系来实现一致性。首席研究员强调，没有这种封闭关系，一个好的封闭关系，任何积分方程都不能达到高一致性，也不能达到精度。将进行蒙特卡罗分子模拟和分子动力学来确定吸附机理并对理论进行验证。

ABSTRACT CTS-0114123Lee, Lloyd L/ U of Oklahoma Nanostructured materials are currently being developed for use in molecular adsorption and molecular recognition. The design and selection of sensor materials [65,66] in commercial use have been mostly done by trial and error and qualitative thinking, rather than with tailor-made specificity and quantitative principles. With the development of the nanostructured materials, such as self-assembled monolayers (SAMs) and dendritic structures, there have been created a vast menu of chemical and physical properties for selection. We need to have a molecular level understanding of the nature and consequence of the molecular interactions at play. This research is aimed at establishing a microscopic framework, using molecular theory and computer simulation, for gas adsorption in three typical nanomaterials: aerogels, zeolites, and starburst dendrimers. This furnishes a quantitative principle rooted in the molecular level that shall aid in the design and development of gas adsorption and molecular recognition devices.There are, broadly speaking, older nanomaterials (e.g., zeolites, membranes, aerogels, activated carbons, etc.) and newer ones (e.g., star polymers, dendrimers, etc.) Whathappens to the gases (fluids) included in these substrates with respect to their molecular distributions, isosteric heats of adsorption, phase behavior, thermodynamic properties, adsorption isotherms, separation efficiency (for mixtures), selective adsorption, and partition coefficients? An accurate molecular theory and well-targeted molecular simulation are needed that give the probabilistic densities of distribution of theconfined gases around the ordered substrates, as well as their theoretical connections to the thermodynamic properties. This is properly the task for our statistical mechanics of adsorption.The principal investigator will develop a new integral equation (IE) theory and perform molecular computer simulation to determine the gas structures (distribution functions) and thermodynamic properties of inclusion gases and gas mixtures around nanostructures. He uses the existing replica Ornsterin-Zernike (ROZ) equations as astarting point. New forms will be developed for the inclusion gas in random as well as regular media, and in rigid as well as deformable adsorbents. The conventional ROZ can treat only inrigidlo matrices. He uses a two-temperature quench procedure to formulate a new equation for responsive systems. In addition, consistency is achieved by designing a new closure relation satisfying a set of exact self-consistency principles. The principal investigator stresses that without this closure relation, a good one at that, no integral equations can achieve high consistency, nor accuracy. Monte Carlo molecular simulations and molecular dynamics will be carried out to determine the mechanism of adsorption and to test the theories.