NIRT: Multiscale Simulation of the Synthesis, Assembly and Properties of Nanostructured Organic/Inorganic Hybrid Material

该提案是响应“纳米尺度科学与工程”（NSF-00-119）的征求而提交的。由此产生的拨款由材料研究部和化学与热系统部共同资助。这项拟议中的研究将在田纳西大学、密歇根大学和弗吉尼亚大学进行。参加会议的还有NIST、混合塑料和塔尔材料。多面体油聚硅氧烷（POSS）分子具有独特的纳米结构。POSS分子具有多面体核心，可以作为多功能的平台，可以合成修饰以包含聚合，粘附，光敏化，结合催化剂物种和改善溶解度的基团。用不同的有机或无机基团独立地功能化POSS立方体的每个角落的能力，赋予了POSS分子组装而成的几乎无限可能的混合纳米结构阵列。根据POSS笼的功能化，所得到的系统可以是固体或液体，或通过交联变成一个网络。它们是一种真正的纳米结构的构建块，通过自我和引导组装，可以转化为一系列非凡的产品，并且由于最近快速合成技术的突破，现在才刚刚进入商业规模的工业。虽然在实验上对POSS系统的化学合成有很多了解，但在分子水平或更高水平上的理论理解却很少。特别是，单个POSS分子在纳米尺度上组装和操纵形成中观和宏观尺度系统的方式尚未得到研究。在这笔拨款中，将开发一个多尺度计算框架来模拟POSS系统的综合和自引导装配。为了在多个层面上解决POSS系统，从量子力学到中尺度和宏观，主要研究人员（PI）具有从电子结构计算到分子模拟的必要专业知识。这种专门知识将应用于三个初步问题：(1)交联POSS网络的结构；(2)纳米结构相预测；(3)模板化纳米结构薄膜。基于PI的专业知识和可用代码，已经开发出了描述这些系统的可行的多尺度建模路线。随着建模工作的发展，将进行修改。开发的模拟代码将在公共领域内，记录在用户手册和技术报告中，并分发给用户社区。这些技术将使预测成为可能，基本上从第一性原理出发，预测无机/有机混合纳米结构系统的物理和结构特性。% % % * * *

This proposal was submitted in response to the solicitation "Nanoscale Science and Engineering" (NSF-00-119). The resulting grant is co-funded by the Divisions of Materials Research and Chemical and Thermal Systems. The proposed research will be carried out at the Universities of Tennessee, Michigan and Virginia. Also participating are NIST, Hybrid Plastics and Tal Materials.Polyhedral oilgomeric silsesquioxane (POSS) molecules are unique nanometer-sized structures. POSS molecules have a polyhedral core which can be multifunctional and serve as platforms that can be synthetically modified to contain groups for polymerization, adhesion, light sensitization, binding catalyst species, and improved solubility. The ability to independently functionalize each corner of a POSS cube with different organic or inorganic groups confers a nearly infinite array of possible hybrid nanostructures made of assemblies of POSS molecules. Depending on the functionalization of the POSS cages, the resulting systems can be solid or liquid, or on crosslinking turned into a network. They are a truly nanostructured building block, which, through self-and guided-assembly, can be transformed into a remarkable array of products, and due to recent breakthroughs in rapid synthesis technology, are only just now becoming available to industry on a commercial scale.While much is known experimentally about the chemical synthesis of POSS systems, very little theoretical understanding exists at the molecular level or beyond. In particular, the way in which individual POSS molecules can be assembled and manipulated at the nanoscale to form meso-and macro-scale systems has not been studied. In this grant a multiscale computational framework will be developed to simulate the synthesis and self-and guided-assembly of POSS systems.In order to address POSS systems at many levels, beginning at the quantum mechanical through to the mesoscale and macroscopic, the principal investigators (PI's) have the requisite expertise ranging from electronic structure calculations to molecular simulation. This expertise will be applied to three initial problems: (1) structure of cross-linked POSS networks; (2) nanostructured phase prediction; and, (3) templated nanostructured thin films. Feasible multiscale modeling routes to describing these systems have been developed, based on the expertise and codes available among the PI's. Modifications will be made as the modeling effort evolves. The simulation codes developed will be in the public domain, documented in user manuals and technical reports, and distributed to the user community. These techniques will enable the prediction, essentially from first principles, of the physical and structural properties of hybrid inorganic/organic nanostructured systems. %%%***