Preparation, adsorption and aggregation behavior of sodium oleyl sulfate with high double bond retention

Abstract Sodium oleyl sulfate with high double bond retention of 95.69 % (SOS-95) was successfully prepared by using sulfamic acid as a sulfating reagent, and its structure was identified by Fourier transform infrared (FT-IR) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR). Compared with octadecyl sodium sulfate (OSS) and sodium oleyl sulfate (SOS-77) with double bond retention rate of 77.38 %, the surface properties such as equilibrium surface tension, dynamic surface tension, and dynamic contact angle were analyzed. The results showed that SOS-95 had a lower surface tension (γcmc) of 31.96 mN/m, and the lower critical micelle concentration (CMC) of 0.028 mmol/L. Moreover, it had good adsorption, diffusion and relatively excellent spreading performances, the contact angle can reach as low as 56.87 ° in 130 s. The aggregation behavior was researched by transmission electron microscopy (TEM), and the sizes of the aggregates were analyzed by dynamic light scattering (DLS). The results showed that sphere-like micelles were formed spontaneously by aqueous solutions of SOS-95 at CMC, and the higher the concentration, the larger the size of the aggregates. Polarized optical microscopy (POM) combined with small Angle X-ray scattering (SAXS) analysis confirmed that lamellar phase liquid crystal structure with Maltese cross flower was formed in aqueous of SOS-95.