二氧化硅粒子尺寸与微结构调控的分子机制研究

二氧化硅（SiO2）粒子尺寸及微结构的精确调控，是其进一步应用推广所必须解决的关键问题。本项目以经典的氨水催化四乙氧基硅烷（TEOS）水解/缩合制备SiO2粒子方法(Stöber法)为模型体系，对SiO2粒子尺寸和微结构随氨水浓度变化的现象进行系统定量研究。1）监测TEOS的水解和缩合速率，捕获反应初期水解和缩合产物的分子结构信息，在分子水平上理解氨水浓度对TEOS水解/缩合动力学的影响；2）系统研究不同氨水浓度下SiO2粒子成核、生长和聚集过程及其微结构特征；3) 建立统一的理论模型，阐述TEOS水解/缩合平衡与SiO2粒子成核/聚集/生长过程之间的关系，揭示Stöber法中SiO2粒子尺寸和微结构的变化规律，以期为SiO2及其他相关胶体粒子的设计与精准合成调控奠定理论和方法学基础。

Precise regulation of the sizes and microstructures of silica particles is vital important to promote their practical and broader applications. In this project, we systematically and quantitatively investigate the variations in sizes and microstructures of silica particles with ammonia concentration in the classical Stöber method, which concerns the preparation of silica particles by ammonia catalyzed hydrolysis/condensation of tetraethoxysilane (TEOS). In this project, we aim at: 1) Understanding the effect of ammonia concentration on kinetics of hydrolysis/condensation of TEOS at molecular level, by following the rates and identifing molecular structures of the products derived from TEOS hydrolysis/condensation. 2) Investigating systematically the nucleation/aggregation/growth processes of the silica particles and microstructures of the particles prepared under different ammonia concentrations. 3) Proposing a unified model to describe the relationship between hydrolysis/condensation balance of TEOS and nucleation/aggregation/growth processes of silica particles, and therefore unraveling the variations in sizes and microstructures of silica particles in the Stöber method. Such a study is expected to provide theory and methodology for design and accurate syntheses of silica and other related colloidal particles.