Effect of EG and low temperature on solution behaviors of wormlike micelles

Wormlike micelles (WLMs) are prepared in ethylene glycol (EG)-aqueous mixed solution. Gemini surfactant, 2-hydroxyl-propanediyl- α,ω -bis-(dimethyldodecylammonium bromide) and sodium benzoate were used, referred as 12-3(OH)-12 and NaBen respectively, to construct WLMs. The effect of EG on WLMs was investigated by rheological measurements. Steady rheological responses of mixed solution slide down like a terrace with the displacement of water by EG. Dynamic rheology spectra shift towards high angular frequency and the mixture transformed from viscoelastic to less viscous fluid. The addition of NaBen into 12-3(OH)-12 solution causes similar salt effect within different EG content. However, the peaks of viscosity and relaxation time both shifts towards high NaBen concentration and the maximum values decreases one order of magnitude when EG content varying from 0% to 20%. All rheological behaviors were investigated below room temperature. The results show that the WLMs system still keeps desirable rheological properties in EG-water system. The evolution of sample viscosity upon temperature conforms to Arrhenius law. The study provides deep comprehension on the self-assembly behavior of WLMs in low-temperature region.