Coarse-grained Molecular Dynamics Simulation for Surfactant Aqueous Solution Based on the martini Force Field

The rheological behaviors in a binary system of cetyltrimethylammonium chloride (CTAC) and sodium salicylate (NaSal) under Couette flow were studied by molecular dynamics simulations using the coarse-grained MARTINI force field and explicit CG water solvent. The results show that, while the CTAC concentration and molar ratio increase, the shear viscosity increases; but the shear viscosity decreases with the temperature increasing. On condition of high shear rate condition, for the relationship between shear viscosity and the molecule number of the final longest micelle, the molecular number of the final longest micelle decreases with the temperature and shear rate increasing, corresponding to the decreasing of shear viscosity. The molecular number of the final longest micelle on the three binary systems (CTAC/NaCl, CTAC/NaSal, CTAC/NamSal) ranks as follows: N_CTAC/NamSal > N_CTAC/NaSal > N_CTAC/NaCl, and the shear viscosity of the three systems can be ranked as η_CTAC/NaCl < η_CTAC/NaSal < η_CTAC/NamSal.