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 presence of 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 counter ions, which reduces electrostatic screening and increases the overall energy Phi linearly with micelle length. Micelle scission occurs when Phi exceeds a threshold value, independent of S.