(685a) Enhanced Sampling Methods for Modulating Density Fields

Driven by hydrophobic effects, aqueous surfactant solutions self-assemble into mesostructures with distinct symmetries, such as micelles, vesicles and bilayers. Molecular simulations play an important role in connecting the molecular characteristics of the surfactants to the properties of the mesostructures, the thermodynamic stability of the mesophases, and transitions between them. However, studying these mesostructures using straightforward simulations can be challenging, due to the large separation in timescales between the relaxation of individual molecules and that of the mesostructures. Here, we present an enhanced sampling simulation technique to address this challenge. Our approach involves organizing the molecules of interest into structures with well-defined symmetries, through the application of an external potential, which biases the molecular density field. The response of the system to the biasing potentials allows us to estimate mesostructure properties, as well as the thermodynamic stability of a particular mesophase with respect to another.