A new series of pH-responsive Gemini surfactants with 2-pyrrolidone head groups, N, N′- dialkyl-N, N′-di (ethyl-2-pyrrolidone) ethylenediamine (Di-C n P, where n= 6, 8 10, 12), were synthesized and characterized by 1H NMR, 13C NMR, ESI-MS, and elemental analysis. The surface activity and micellization behavior at acidic, neutral, and basic conditions were characterized by equilibrium surface tension and fluorescence ...