Adsorption and thermodynamic properties of dissymmetric gemini imidazolium surfactants with different spacer length

Abstract

A series of dissymmetric gemini imidazolium surfactants with different spacer length ([CmCsCnim]Br2, m + n = 24, m = 12, 14, 16, 18; s = 2, 4, 6) were synthesized and characterized by 1H NMR and ESI-MS spectroscopy. Their adsorption and thermodynamic properties were investigated by the surface tension and electrical conductivity methods. Consequently, the surface activity parameters (cmc, γcmc, πcmc, pC20, cmc/C20, Γmax, Amin) and thermodynamic parameters (ΔGmθ, ΔHmθ, ΔSmθ) were obtained. The effects of the dissymmetry (m/n) and the spacer length (s) on the surface activity and micellization process of surfactants have been discussed in detail.