A polymerizable cationic gemini surfactant, [CH(2)dC(CH3) COO(CH2)(11)N+ CH3)(2)CH2]2 center dot 2Br(-), 1 has been synthesized and its basic interfacial properties were investigated (in water and in the presence of 0.05 M NaBr). For comparison, the properties of monomeric surfactant corresponding to 1, CH(2)dC(CH3) COO(CH2)(11)N+(CH3)(3)center dot Br-, 2, were also investigated. Parameters studied include cmc (critical micelle concentration), C-20 (required to reduce the surface tension of the solvent by 20 mN/m), gamma(cmc) (the surface tension at the cmc), cmc (the maximum surface excess concentration at the air/water interface), A(min) (the minimum area per surfacatant molecule at the air/water interface), and cmc/C-20 ratio (a measure of the tendency to form micelles relative to adsorb at the air/water interface). For the polymerizable gemini surfactant, 1, the methacryloxy groups at the terminal of each hydrophobic group in a molecule have no contact with the air/water interface in the monolayer, whereas for the corresponding monomeric surfactant, 2, the methacryloxy group contacts at the interface forming a looped configuration like a bolaamphiphile. Polymerized micelles of the gemini surfactant are fairly small monodisperse and spherical particles with a mean diameter of 3 nm.