Effect of polymer on dynamic interfacial tensions of sulfobetaine solutions

The effect of different types of polymers, partly hydrolyzed polyacrylamide (HPAM), hydrophobically modified polyacrylamide (HMPAM) and co-polymer, on the dynamic interfacial tensions (IFTs) of benzyl substituted alkyl sulfobetaine (BSB) against n-alkanes, kerosene and crude oil have been investigated by a spinning drop interfacial tensiometer. The influence of polymer concentration on IFTs was expounded. The experimental results show that betaine has high interfacial activity and the addition of polymer has great influence on both dynamic IFT behaviors and equilibrium values between surfactant solution and n-alkanes mainly by modifying the interfacial molecular arrangement on the interface. However, the addition of polymer affects the dynamic IFTs of surfactant solution against kerosene and crude oil, but has little effect on the equilibrium IFT values. Active substances existing in kerosene and the in situ produced petroleum acidic soaps play a synergistic effect with betaine to reduce the IFTs. The increase of viscosity of aqueous phase caused by polymer influence the adsorption of the surfactant at the interface, slowing down the decrease of IFTs and changing the minimum transient IFT values.