Rheological Investigation of Wormlike Micelles Based on Gemini Surfactant in EG–Water Solution

Abstract

AbstractThe self‐assembly behavior of gemini surfactants in ethylene glycol (EG)‐water (5/95, v/v) mixed solvent was investigated by rheological measurements at 10 °C. The influence of molecular structure of the gemini surfactant and added hydrotrope on the solution properties was studied. Sodium salicylate (NaSal) showed stronger ability to induce 2‐hydroxyl‐propanediyl‐α,ω‐bis‐(dimethyldodecylammonium bromide), referred to as 12‐3(OH)‐12, to form wormlike micelles than sodium benzoate. Less NaSal is required to promote a sphere to rod transition and to reach the peak viscosity. Moreover, the concentrations of hydrotrope and gemini surfactant are both lower than conventional single‐chain surfactant systems to reach a comparable viscosity. The strong hydrophobicity of gemini surfactants and hydrotropes is responsible for the high efficiency in forming wormlike micelles in EG/water systems. The geometric structure of gemini surfactants also plays a vital role in self‐assembly into wormlike micelles. Dimethylene‐1,2‐bis‐(dodecyl dimethylammonium bromide), referred to as 12‐2‐12, shows absolute superiority over 12‐3(OH)‐12 in constructing wormlike micelles. The present study will be helpful for developing de‐icing fluids and anti‐freezing solutions, which need rheology control in EG‐aqueous medium at low temperature.