Self-Assembly of the Cationic Gemini Surfactant in Water: From Elastic Gels to Viscoelastic Solutions

Gemini surfactants, composed of two surfactant monomers, are likely to self-assemble into viscoelastic fluids in water at low concentrations. Here, the aggregation behaviors of quaternary ammonium gemini surfactant with a hydroxyl group on the spacer (16-3OH-16) have been studied in the dilute aqueous system by rheological techniques, small angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and other characterizations. At room temperature, the samples behave as elastic gels. The structure and morphology of gels were confirmed by SAXS and SEM characterizations. Due to the hydroxyl group on the spacer of 16-3OH-16, the gels are more stable than those formed by 16-3-16. At high temperature, the gels transform into wormlike micelles and behave as viscoelastic fluids. The obtained results would help to construct complexed fluids with structure tailorable gemini surfactants.