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

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 (H-1 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 (gamma(cmc)) 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 degrees 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. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Sodium oleyl sulfate with high double bond retention rate of 95.69% (SOS-95) was successfully prepared using sulfamic acid as a sulfating reagent. The surface properties and aggregation behavior of SOS-95 were analyzed, showing its potential application prospects in the field of surfactants.