Silica is one of the most important inorganic materials, and has been drawing a growing number of attentions in the field of organic/inorganic composite materials. In this paper, research progress on methods and mechanisms of chemical modification as well as applications of modified silica particles are reviewed in detail. Mechanisms of coupling method, surface grafting methods (“grafting from” and “grafting onto” included) and one-step method are discussed along with the comments on key points and advantages of these methods. The methods of “grafting from” based on conventional free radical polymerization, atom transfer radical polymerization and reversible addition-fragmentation chain transfer polymerization are discussed, whereas “grafting on” based on ring-opening addition reaction, “click chemistry” and esterification reaction are described. Generally, endowing silica surface with functional groups for further reaction by silane coupling agents is essential, and silane coupling agents and their modification mechanisms are introduced firstly. In addition, one-step method is also discussed here. At the same time, significances of surface modification which are improvement on dispersibility, endowing silica with functionality and improvement on compatibility are summarized. The dispersibility of surface modified silica particles in organic solvents or organic matrix is improved. The modified silica particles are functioned by the groups or polymers which are grafted on their surfaces. The adhesive forces between organic phase and inorganic phase are enhanced since the modified silica particles are dispersed well in the organic matrix. And the modified silica particles are expected applications in fabricating new materials. Contents
1 Introduction
2 Methods and mechanisms of chemical modification
2.1 Coupling method
2.2 Surface grafting method
2.3 One-step method
3 Significance of surface modification
3.1 Improvement on dispersibility
3.2 Endowing silica with functionality
3.3 Improvement on compatibility
3.4 Other significances
4 Conclusions and outlook