Zheng Zhu, Xiaohao Lu, Liangliang Lin, Hujun Xu, Haiyan Gao
May 12, 2021
In the present study, the micelle aggregation numbers and hydrodynamic radius distributions of the gemini surfactants (abbreviated as C m -(EO) n -E-C m (m = 12–16, n = 1, 2)) were investigated by fluorescence spectroscopy and dynamic light scattering (DLS). The rheological properties of these surfactants were determined using a rheometer. The Surfactants C 14 -(EO)-E-C 14 and C 16 -(EO)-E-C 16 formed worm-like micelles at a concentration of 200 mmol/L. It was found that longer hydrophobic chains or shorter linkage groups promoted the growth of worm-like micelles. Then, the influence of the inorganic salt NaBr and the organic salt sodium salicylate (NaSal) on the formation and properties of wormlike micelles in aqueous C 16 -(EO)-E-C 16 solutions at a surfactant concentration of 20 mmol/L was investigated. The results showed that NaSal could penetrate deeper into the hydrophobic group of the micelle due to its good hydrophobic interaction, which promoted micelle growth and resulted in worm-like micelles. In addition, the tested systems showed a Maxwell behavior at lower frequencies, but deviated from the Maxwell mode at higher frequencies. Finally, the formation of worm-like micelles was also verified by micro polarity measurements.