Study on the transformation from linear to branched wormlike micelles: An insight from molecular dynamics simulation

Transformation from linear to branched wormlike micelle generally results in the dramatic loss of viscoelasticity. In this study, adopting Coarse-grained molecular dynamics simulation, the conformational transformation was studied in a binary system of cetyltrimethylammonium chloride (CTAC) and sodium salicylate (Nasal). A gross conformation diagram of micelle at different CTAC concentrations and molar ratios of CTAC/Nasal indicates that the branched structure could form at zeta potential lower than 32mV. Further, the dynamic process displays that four sequential stages, approaching, forming salt bridge, yielding stalk, and coalescing together, involve in this transformation. And a fascinating process, an organic salt bridge first form between two approaching micelles and then induces the surfactant jump out to form stalk, was observed. In addition, some rational strategies were proposed to reduce the probability of this conformational transformation. Our study provides a molecular-level understanding of transformation behaviour from linear to branched wormlike micelles.