Characterization of Silica Sol Particle Prepared by Sol-Gel Reaction from Sodium Silicate Solution

Abstract Silica sol was prepared from the mixture of sodium silicate solution and oxidized silicate solution in which sodium had beenremoved by sol-gel process. The properties of sodium silicate solution and silicate solution thus prepared were characterized byyellow silicomolydate method. Moreover, the formation and growth of silica sol from sodium silicate solution was investigated.Sodium silicate solution with 2% of SiO 2 contains 95% of reactive silicate, and 50% of reactive silicate participates sol-gel reac-tion. From the results of FT-IR analysis, it was found that the intensity of silanol bond decreased and the intensity of siloxanebond increased with increasing reaction temperature. Zeta potential of silica sol prepared at each condition was -40~-60 mV andit could be known that silica sol in this study was well dispersed. The silica sol with 5~10 nm size could be prepared by heatingthe mixed solution of sodium silicate and silicate solution. And the silica sol grew into about 20 nm as silicate solution was addedto silica sol solution.