Quantitative modeling of threadlike micellar solution rheology

mesoscopic simulation method, the “pointer algorithm,” is here shown to capture accurately the rheology of a variety of surfactant solutions, including CTAB/NaNO 3 , CPyCl/NaSal, and CTAB/NaSal, at different salt and surfactant concentrations presented in the literature. In addition, correlations derived from this method are shown to allow the average micelle length ⟨ L⟩ to be estimated from G_min^^'/G_min^^''=0.317(⟨ L⟩/l_e)^0.82 where G_min^^' / G_min^^'' is the ratio of storage to loss modulus at the frequency where G ″ exhibits a local minimum, and l_e is the entanglement length, which can be estimated from the modulus. We also obtain from the pointer algorithm a formula whereby the micelle breakage time ( τ br ) can be estimated from the longest relaxation time ( τ_R ). The pointer algorithm’s predictions are also shown to match those of a more microscopic slip-spring model, which had been previously validated by comparison to polymer rheological data. Thus, the work provides both a method and example estimates of these parameters as functions of surfactant and salt concentration, filling a major gap in characterization of these solutions. Finally, we investigate the determination of the micelle persistence length from high-frequency data.