Microstructures and rheology of micellar surfactant solution by Brownian dynamics simulation

In this paper, three-dimensional Brownian dynamics simulation has been conducted for dilute micellar surfactant solution under a steady shear flow. The rodlike micelle in surfactant solution is assumed as a rigid rod made up of lined-up beads. The Lennard-Jones potential and soft-sphere potential are employed and taken as the inter-bead potentials for end-end beads and interior-interior beads, respectively. The motion of the rodlike micelles is determined by solving the translational and rotational equations for each rod under hydrodynamic drag force, Brownian force and inter-rod potential force. Velocity Verlet algorithm has also been exerted in the simulation. The micellar network structure is formed at low shear rates and destroyed by high shear rates. The computed shear viscosities and the first normal stress coefficient represent shear thinning characteristics. The paper reveals the relation between rheology and microstructure of surfactant solution at different shear rates. The effect of surfactant solution concentration rested on the micellar structures and rheological properties has also been investigated.