Study on Stabilizing Emulsion by Mixing Nano-silica and Cationic Surfactants with Different Chain Length

Abstract

Considering the interaction between the electronegative nano-silica (NS) and cationic surfactant, this paper aims at studying the effect of NS modified by cationic surfactants with different chain length on emulsion behavior. These effects on emulsion behavior were investigated at two aspects: emulsion stability and rheological characteristics. Experimental results indicated that flocculation of nano-silica becomes easier with longer alkane chains. While the chain length increases within the studied concentration range, the threshold concentration of surfactants at which the intermediate phase emulsion appears decreases. For NS and DETAB together in dispersion, no phase inversion appeared. The NS surface hydrophilic-lipophilic balance was changed due to the enwind of the alkane chain. Longer alkane chain adsorbs on the NS surface and reaches saturation at the same surfactant concentrations more easily due to the different enwind degrees of alkane chains. It is suggested that the different surfactant chains had different enwind degrees on the liquid-liquid interface. Rheological experiments show that the emulsion has shear dilution and elasticity.