English

Nonmonotonic concentration dependence of the self-diffusion coefficient of surfactants in wormlike micellar solutions

Soft Condensed Matter 2025-02-19 v1

Abstract

We investigate the concentration dependence of surfactant diffusion in wormlike micellar solutions using dissipative particle dynamics simulations. The simulations show that the self-diffusion coefficient of surfactants exhibits a nonmonotonic dependence on the surfactant concentration, as observed in previous experiments. We quantitatively reveal that this nonmonotonic behavior results from the competition between micellar center-of-mass diffusion and surfactant diffusion within micelles by decomposing the mean-square displacement of surfactants into the corresponding contributions. Furthermore, our detailed analyses demonstrate how the competition between the two diffusion mechanisms is governed by the aggregation number distribution, the dynamics of individual surfactants and micelles, and the kinetics of micellar scission and recombination.

Keywords

Cite

@article{arxiv.2502.12472,
  title  = {Nonmonotonic concentration dependence of the self-diffusion coefficient of surfactants in wormlike micellar solutions},
  author = {Yusuke Koide and Takato Ishida and Takashi Uneyama and Yuichi Masubuchi},
  journal= {arXiv preprint arXiv:2502.12472},
  year   = {2025}
}