2016/10/26 by Subas Dhakal, Radhakrishna Sureshkumar
Chemistry · Materials Science · Physics and Astronomy · #Aqueous solution #Breakage #Chemical physics #Chemistry #Composite material #Computational chemistry #Diffusion #Electrostatics and Colloid Interactions #Material Dynamics and Properties #Materials science #Micelle #Molecular dynamics #Physical chemistry #Physics #Pulmonary surfactant #Relaxation (psychology) #Stress relaxation #Surfactants and Colloidal Systems #Thermodynamics #Viscosity #cond-mat.soft
paper · pdf · doi:10.1103/physreve.96.012605
published as Phys. Rev. E 96, 012605 (2017) · 4 pages, 5 figures, Supplementary animation (S1)
arxiv created 2016/10/26 · openalex publication_date 2017/07/24 · arxiv updated 2017/08/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We investigate the mechanisms of anomalous diffusion in cationic surfactant micelles using molecular dynamics simulations in the presence of explicit salt and solvent-mediated interactions. Simulations show that when the counterion density increases, saddle-shaped branched interfaces manifest. In experiments, branched structures exhibit lower viscosity as compared to linear and wormlike micelles. This has long been attributed to stress relaxation arising from the sliding motion of branches along the main chain. Our simulations reveal a mechanism of branch motion resulting from an enhanced counterion condensation at the branched interfaces and provide quantitative evidence of stress relaxation facilitated by branched sliding. Furthermore, depending on the surfactant and salt concentrations, which in turn determine the microstructure, we observe normal, subdiffusive, and superdiffusive motions of surfactants. Specifically, superdiffusive behavior is associated with branch sliding, breakage and recombination of micelle fragments, as well as constraint release in entangled systems.