Abstract

A series of novel cationic–non-ionic heterogemini surfactants (C_n-1EC-s-C_m where n and m represents the hydrocarbon chain length of fatty acid and aliphatic amine, n=12, 14, 16, 18, m=12, 14, 16) were synthesized from fatty acid, epichlorohydrin and aldciphatic amine. The chemicals tructures of the surfactants were characterized by IR spectra, NMR, ESI-MS and elemental analysis. Their critical micelle concentrations (CMC) in the aqueous solutions were determined by surface-tension at 25°C.Relationship between γ_cmc and hydrophobic chain length was established which showed a large increase upon increasing of chain length with ester. The surface-tension measurements ofC_n-1EC-s-C_m showed a low CMC, which greatly improve the efficiency in lowering the surface tension. Furthermore, adsorption and micellization behavior of C_n-1EC-s-C_m were investigated by measuring minimum average area per surfactant molecule and standard free energy.

Keywords: Zwitterionic, heterogemini, surfactants, fatty acid, cationic, non-ionic.

Graphical Abstract