Self-assembly and viscosity changes of binary surfactant solutions: a molecular dynamics study

Jun Zhou, P. G. Ranjith

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)

Abstract

Hypothesis: Structure and self-assembly of surfactants in the solution shows a fundamental influence on its viscosity. Through molecular simulations using Martini force field, synergistic effects in aggregation as well as the viscosity changes of a binary ionic surfactant system can be modelled. Simulations: Coarse-grained molecular dynamics simulations are performed to model the SDS/CAPB binary surfactant solution, and both equilibrium and non-equilibrium methods are used to calculate the viscosity of the equilibrated micellar systems. Findings: Our simulation results indicate that the new version of the Martini force field can provide more reasonable self-assembly of surfactant, both single and binary system. Synergistic effects in micelle formation for SDS/CAPB have been successfully reproduced, that is, the formation of cylindrical micelles or even wormlike micelles at a lower concentration when compared with the pure system. Meanwhile, both equilibrium and non-equilibrium methods provide quantitatively comparable viscosity for each system. For pure micellar system, the viscosity linearly increases with the total concentration. Nevertheless, our simulation fails to capture the viscosity enhancement of the solution in corresponding with the formation of rodlike or wormlike micelles, and a full parameter optimization of force field is still necessary.

Original languageEnglish
Pages (from-to)250-257
Number of pages8
JournalJournal of Colloid and Interface Science
Volume585
DOIs
Publication statusPublished - Mar 2021

Keywords

  • CAPB/SDS mixture
  • Molecular dynamics
  • Morphology transition
  • Surfactant micelle
  • Viscosity

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