As surfactants for crude oil emulsions, poly[N,N-(dimethylamino) ethyl methacrylate-b-poly(ethylene glycol) methyl ether methacrylate-b-lauryl methacrylate] (PDMA-b-PPMA-b-PLMA) triblock copolymers were synthesized via reversible additionfragmentation chain transfer (RAFT) polymerization and characterized by gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. The copolymers exhibited high interfacial activity which could be tuned by simply adjusting the solution pH, and remarkably reduced the dodecane/water interfacial tension from 52.8 to 2.1 mN/m, producing stable dodecane-in-water emulsions even at a low concentration of 0.5 mg center dot mL1. Utilization of these copolymers in Shengli crude oil further confirmed their emulsification capacity. The apparent viscosity of crude oil reduced from 34?000 to 350 mPa center dot s after emulsification at 20 degrees C, and the formed emulsions exhibited long-term stability for above 3 months. Due to the balanced hydrophilicity and hydrophobicity, PDMA(22)-PPMA(27)-PLMA(36) proved to be the most efficient surfactant, which generated stable O/W emulsion with the smallest dosage.