Determination of Critical Micelle Concentrations (CMC) of Surfactants Based on Viscosity Calculations by Coarse-Grained Molecular Simulation

Studying self-assembly in surfactant solutions by experimental methods or molecular modelling is importance for many industrial processes. The molecular modelling can provide valuable information for the behavior of surfactant in the solution and the prediction of surfactant properties such as critical micelle concentration (CMC). In this proposal, alternative methods for determining the critical micelle concentration (CMC) are proposed using coarse-grained molecular dynamic simulations. In the literature, a common calculation of the CMC value is the free (unassociated) surfactant concentration in the presence of micellar aggregates by using molecular dynamic simulations. The simulations of micellizing systems have observed a decrease in the free surfactant concentration with total surfactant concentration. In the present study, we will calculate the CMC value from viscosity method by applying different shear rate to the system. We will provide deep understanding about the effect of applying different shear rate into the surfactants water systems especially in Newtonian and non-Newtonian regions. We will determine zero-shear viscosity by using empirical model to fit the simulation data of viscosity versus shear rate. The critical micelle concentration (CMC) of surfactants can be calculated from the variation of viscosity in both the premicellar and micellar regions.