Study on the synthesis and properties of Gemini surfactant with ester spacers

Abstract A group of cationic Gemini surfactants with ester spacers, C 12 -E 2 -C 12 , C 16 -E 2 -C 16 , C 18 -E 2 -C 18 , were synthesized and confirmed by IR, 1 H NMR and MS. The surface parameters of the synthesized Gemini surfactants including: the critical micelle concentration ( CMC ), the surface tension value at CMC ( γ CMC ), efficiency (p C 20 ), maximum surface excess ( Γ max ) and minimum surface area ( A min ), were obtained from surface tension measurements. These Gemini surfactants showed higher surface activity than the traditional monomeric surfactants. The thermodynamic parameters of the micellization process from conductivity measurements showed that the micellization was a spontaneous and exothermic process, and the micellization process became less favorable with decreasing alkyl chain length and increasing temperature. The micro polarity was evaluated from steady-state fluorescence spectra. It was found that the micelle aggregation number of C n -E 2 -C n aqueous solution gradually increased with the increase of alkyl chain.