Viscoelastic micellar system of mixed surfactin and octadecyl trimethyl ammonium chloride

Abstract

Surfactin is a kind of lipopeptide biosurfactant with good performance. In order to solve the difficulty of surfactin thickening, this study investigated the new viscoelastic micellar system composed of surfactin and octadecyl trimethyl ammonium chloride (OTAC) and its rheological properties. The influences of mass ratio, pH, and temperature on the rheological properties of the system were studied. Under optimized mass ratio and pH, the maximum viscosity of surfactin/OTAC (4.5/7.5 w/w, pH = 5.34) is obtained as 13,904 mPa s. The flow curves of surfactin/OTAC micelle system can be described by Cross constitutive equation. The rheological properties of surfactin/OTAC viscoelastic micelle systems are obtained, including thixotropy, viscoelasticity, and viscositytemperature properties. The research on the new surfactin/OTAC system expanded the viscoelastic micelle systems of microbial surfactant series, which was expected to provide the rheological basis for the research of the surfactin micellar systems and be applied to the development and production of daily chemical industry, oil recovery, and other fields.