Composites of Colloidal Silica Crystals in Non-crystalline Polymers

一种新型复合材料的合成将比任何已知的聚合物复合材料具有更高度有序的微观结构。复合材料将由单分散的胶体硅球组成，以晶体阵列的形式分布在无定形聚合物中，如聚甲基丙烯酸甲酯和聚丙烯酸乙酯。晶体状的秩序将使它们成为可见光和红外光的高度选择性过滤器，可以通过粒子密度的变化来调节，从而通过布拉格散射来拒绝任何波长。该复合材料将通过溶胶-凝胶法合成单分散的直径为100 nm的二氧化硅颗粒，对二氧化硅表面进行改性使其与单体相容，在单体中自发或受剪切力形成二氧化硅胶体晶体，并对单体进行聚合。改性后的二氧化硅颗粒和复合材料将通过固态C-13和Si-29核磁共振波谱进行分析。胶体二氧化硅和复合材料的制备和化学表征将在Ford教授的研究组进行，光散射和流变学表征将在物理系Bruce J. Ackerson教授的实验室进行。复合材料中分散颗粒的排列顺序对其机械性能的影响是非常重要的，但目前尚不清楚。玻璃和弹性体聚合物复合材料的颗粒密度和二氧化硅颗粒大小变化很大，将提供给辛辛那提大学的James E. Mark教授，以研究其机械性能。

The Synthesis of a new kind of composite materials will be carried out that has a more highly ordered microstructure than any known polymer composites. The composites will consist of monodisperse colloidal silica spheres distributed as crystalline arrays in amorphous polymers such as poly(methyl methacrylate) and Poly(ethyl acrylate). Crystal-like order will make them highly selective filters of visible and infrared light that can be tuned by variation of the particle density to reject any wavelength by Bragg scattering. The composites will be prepared by sol-gel synthesis of monodisperse 100 nm diameter silica particles, modification of the silica surface to make it compatible with monomer, formation of colloidal crystals of silica in monomer spontaneously or by shear forces, and polymerization of the monomer. The modified silica particles and the composites will be analyzed by solid state C-13 and Si-29 nuclear magnetic resonance spectroscopy. The preparation and chemical characterization of the colloidal silica and the composites will be performed in Professor Ford's research group, and light scattering and rheological characterization will be performed in the laboratory of Professor Bruce J. Ackerson of the Department of Physics. The effects of ordering the dispersed particles in a composite on its mechanical properties are fundamentally important to understand, but presently unknown. Glassy and elastomeric polymer composites having a wide variation of particle density and particle size of the silica will be provided to Professor James E. Mark of the University of Cincinnati for investigation of their mechanical properties.