Abstract: Effect of surfactants on viscosity and stability of silica colloids was investigated. Different surfactants were directly added and then viscosity changes and stablity were determined. It showed the viscosity reduced after anionic surfactant added, the CMC of surfacant is about 4.6×10~(-3) mol/L, the stablity increased reversly, the extremum is about 1.43×10~(-3) mol/L. It was speculated that the viscosity reduction was relied on the covering process of SDBS on the colloids particles, but stablity mainly because of formation of micelle and absorption of SDBS was disadvantageous. The stablity could be increased by addition of anionic and nonionic surfactant, but reduced by cationic surfactant.

Key words: surfactant%silica colloids%stablity%viscosity