AUTHOR=Lavagnini Ennio , Booth Jonathan , Helm Katy , El-Benni Ferdaous , Warren Patrick B. , Bray David J. , Anderson Richard L. TITLE=Simulating micelle self-assembly to assess potential for viscosity build in surfactant formulations JOURNAL=Frontiers in Soft Matter VOLUME=4 YEAR=2024 URL=https://www.frontiersin.org/journals/soft-matter/articles/10.3389/frsfm.2024.1341445 DOI=10.3389/frsfm.2024.1341445 ISSN=2813-0499 ABSTRACT=

Self-assembly of surfactants into complex structures is key to the performance of many formulated products, which form a significant fraction of the world’s manufactured goods. Here we adopt the dissipative particle dynamics simulation approach to explore the self-assembly process of surfactants, with the aim of understanding what information can be obtained that may correlate with an increased zero-shear viscosity of surfactant based products. To this end we experimentally measured the zero-shear viscosity of mixed micelle systems comprised of cocoamidopropyl betaine (CAPB) and sodium lauryl sarcosinate (SLSar), as a function of the CAPB/SLSar mass ratio and pH, and characterised the early stages of self-assembly of the same systems computationally. From simulation we identify three distinct behaviors in the micellar self-assembly process (logarithmic, linear and cubic growth) which we find show some degree of correlation with the experimental zero-shear viscosity. Owing to the relatively short simulation times required, this may provide formulation scientists with a practical route to identify regions of interest (i. e. those with a desired zero-shear viscosity) prior to synthesising de novo (potentially natural) surfactants.