Dynamics and Scission of Rodlike Cationic Surfactant Micelles in Shear Flow

Flow-induced configuration dynamics and scission of rodlike micelles are studied for the first time using molecular dynamics simulations in the presence of an explicit solvent and salt. Predicted dependence of tumbling frequency and orientation distribution on shear rate S agrees with mesoscopic theories. However, micelle stretching increases the distance between the cationic head groups and adsorbed counterions, which reduces electrostatic screening and increases the overall energy Φ linearly with micelle length. Micelle scission occurs when Φ exceeds a threshold value, independent of S.