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

该提案是应《纳米科学与工程》(NSF-00-119)的征集而提交的。由此产生的赠款由材料研究部门以及化学和热系统部门共同资助。这项拟议的研究将在田纳西大学、密歇根大学和弗吉尼亚大学进行。参与的还有NIST、杂交塑料和Tal材料。多面体石油单体倍半硅氧烷(POSS)分子是独特的纳米结构。POSS分子具有多面体核心，可以是多功能的，可以作为平台进行合成修饰，以包含用于聚合、粘合、光敏化、结合催化剂物种和改善溶解性的基团。能够独立地使POSS立方体的每个角落具有不同的有机或无机基团的能力赋予了由POSS分子组装而成的几乎无限的可能的杂化纳米结构阵列。根据POSS笼子的功能化程度，得到的体系可以是固体或液体，也可以是通过交联变成网络。它们是一种真正的纳米结构积木，通过自组装和引导组装，可以转化为一系列非凡的产品，由于最近快速合成技术的突破，工业才刚刚可以实现商业规模。虽然关于POSS系统的化学合成在实验上知道很多，但在分子水平或更高的水平上，理论上的了解很少。特别是，单个POSS分子如何在纳米尺度上组装和操纵以形成中观和宏观体系还没有被研究过。在这笔赠款中，将开发一个多尺度计算框架来模拟POSS系统的合成和自组装和引导组装。为了在多个层次上研究POSS系统，从量子力学到介观和宏观，首席研究人员(PI)拥有从电子结构计算到分子模拟的必要专业知识。这些专业知识将应用于三个初始问题：(1)交联POSS网络结构；(2)纳米结构相预测；(3)模板化纳米结构薄膜。基于PI中可用的专业知识和代码，已经制定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。开发的模拟代码将公之于众，记录在用户手册和技术报告中，并分发给用户社区。这些技术将能够基本上从第一性原理预测无机/有机纳米结构混合系统的物理和结构性质。%*

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. %%%***