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

A series of dissymmetric gemini imidazolium surfactants with different spacer length ([C(m)C(s)C(n)im]Br-2, m+n=24, m=12, 14, 16, 18; s=2, 4, 6) were synthesized and characterized by H-1 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, (cmc), (cmc), pC(20), cmc/C-20, (max), A(min)) and thermodynamic parameters (G(m), H-m, S-m) 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.