Enhancement of foamability and foam stability induced by interactions between a hyperbranched exopolysaccharide and a zwitterionic surfactant dodecyl sulfobetaine

Abstract

An aqueous foam containing a zwitterionic surfactant dodecyl sulfobetaine (DSB) and an eco-friendly hyperbranched exopolysaccharide (EPS) secreted by a deep-sea mesophilic bacterium Wangia profunda SM-A87 was prepared for the first time. Compared with singular DSB solution, the EPS/DSB mixing solution exhibited better foamability and foam stability. The minimum DSB concentration (C_DSB) needed to form a stable foam in the EPS/DSB solution was about one hundred times that in the DSB solution, and in a very large C_DSB range, the EPS/DSB foam exhibited a better stability. The enhancement of foamability and foam stability of the complex solution arises from the hydrogen bonding and electrostatic interactions between the EPS and the DSB, and the hyperbranched structure of the EPS. The EPS/DSB foam shows great potential for application in enhanced oil recovery and health-care products.