The self-assembly properties of a series of polymerizable cationic gemini surfactants: Effect of the acryloxyl group

A new series of polymerizable cationic gemini surfactants bearing acryloxyl group in spacer and a variable alkyl chain length were synthesized and their surface active properties alongside with their self-assembly properties were investigated by surface tension measurement, electrical conductivity, fluorescence and dynamic light scattering (DLS) measurements. As compared to single-chain surfmer, this study shows that the gemini surfmers possess low critical micellar concentration (cmc) value and the surface tension value at cmc (γcmc). While compared to corresponding gemini surfactant without acryloxyl group, the introduction of the acryloxyl group into spacer results in a lower cmc value, higher degree of ionization and micropolarity of aggregate. The aggregates with large hydrodynamicradius (Rh) of 70–110 nm as the main component were observed in the surfmer solution, while the size of aggregate constructed by corresponding gemini surfactant without acryloxyl group is far smaller than the former. All the results can be attributed to the existence of intramolecular dipolar interaction between the carbonyl of acryloxyl group and the cationic nitrogen atom. This increases the hydrophobicity and the regularity of the molecule, which induces the formation of tighter and larger size aggregate in comparison with corresponding gemini without the acryloxyl group on the spacer.