Development of materials with ordered structure through phase separation of inorganic-organic mixed sol-gel system

通过无机-有机混合溶胶-凝胶体系的相分离开发有序结构材料

基本信息

批准号：
02555161
负责人：
SOGA Naohiro
金额：
$ 9.02万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

A method of preparing silica gels with micrometer-range inte-rconnected pores by hydrolyzing alkoxysilanes under coexistence of water-soluble polymers has been investigated in detail. Following results have been obtained ;1. Many kinds of water-soluble polymers that have substantial solubility in--water-alcohol mixed solvent can be used in the process.2. Hydrolysis of alkoxysilanes under strongly acidic condition is favored but polycondensation may be conducted also under more basic condition.3. Light scattering profiles of gelling solution exhibited first a continuous development of concentration fluctuation with a fixed periodic wavelength, second a parallel increase of fluctuation and periodic wavelength, and finally a fixation of periodic wavelength and further increase of concentra tion difference. These changes indicate a concurrent occurrence of spinodal decomposition and sol-gel transition in the reacting system.4. Morphology of gels can be controlled by changing starting composition and reaction temperature. Reaction conditions which make a phase separation to occur earlier relative to a sol-gel transition result in coarse morphologies and vice versa. Polymers with high solubility in water-alcohol mixed solvent are favored to obtain gel morphologies with better reproducibility.5. By exchanging solvent phase in wet gels with micrometer-range interconnected pores, the volume and distribution of nanometer-range pores can be, modified to a large extent. This process enables one to tailor pore structure of gels both in micrometer- and nanometer-ranges.

已经详细研究了一种用微米范围的凝胶与千分线凝胶相关的毛孔来制备硅胶在水溶性聚合物共存下通过水解烷基硅烷的孔。已获得以下结果； 1。在此过程中，可以使用许多具有大量溶解性的水溶性聚合物。2。在强酸性条件下的烷氧基硅烷的水解受到利用，但在更基本的条件下也可以进行多头敏。3。胶凝溶液的光散射曲线首先表现出浓度波动的连续发展，其固定周期性波长，其次是波动和周期性波长的平行增加，最后是周期性波长的固定，并进一步增加了浓度差异。这些变化表明在反应系统中同时出现了旋缺链分解和溶胶 - 凝胶转变。4。凝胶的形态可以通过改变起始组成和反应温度来控制。相对于溶胶 - 凝胶过渡的较早发生的反应条件会导致形态粗糙，反之亦然。具有高溶解性的聚合物在水 - 酒精混合溶剂中受到青睐，以获得具有更好可重现性的凝胶形态。5。通过将湿凝胶中的溶剂相与微米范围互连的孔交换，可以在很大程度上修改纳米孔孔的体积和分布。此过程使一个过程可以量身定制胶合体和纳米范围内凝胶的孔结构。