Adsorption and aggregation behavior of oley alcohal based extended surfactant and its mixtures

Abstract

Oley alcohal based extended surfactant, sodium oleyl polyethylene oxide -polypropylene oxide sulfate (OE3P3S), was synthesized and identified by FT-IR and 1H NMR. The adsorption and aggregation behavior of OE3P3S and its mixture with cationic surfactant alkyltrimethylammoniumbromide (ATAB) under different molar ratios were investigated. The static surface tension analysis indicates that the critical micellization concentration(cmc) and the critical surface tension (γcmc) of OE3P3S was 0.72mmol/L, and 36.16mN/m, respectively. The cmc and γcmc values of the binary system were much lower than that of the individual component. And the cmc values of OE3P3S/ATAB=6:4 mixtures decreased with the increase of chain length of the cationic surfactant in the binary system. It was found from the dynamic surface tension that there was a slower diffusion rate of binary system compared to the pure surfactant, and the adsorption processes for OE3P3S/ATAB =6:4 were mixed diffusion-kinetic adsorption mechanism. With a combination of DLS data and TEM measurements, formations of vesicles in OE3P3S/ATAB =6:4 solutions appeared to occur at a concentration of 0.05mmol/L. By studying the formation of liquid crystal structures in emulsion prepared with OE3P3S as the surfactant, it was found that the shape of acquired oil droplets being spherical and homogeneous, and the rheological properties revealed that the emulsion had good storage stability and shear thinning properties.