Numerical simulation of coalescence in oil/water emulsions

The main objective of the project is to determine the role of surfactant molecules in oil/water emulsions. The emulsions in consideration may be stable or unstable with respect to coalescence. The study will include a combination of MC and MD simulations, where the MC part will be used to design the complex water/oil/surfactant systems and to determine equilibrium properties, while MD will be used for simulation of the dynamic molecular behaviour. The model for the oil phase and the surfactants will be the "United Atoms" or "Anisotropic United Atoms" model, whereas the water phase will be modelled with one of the current water models (TIPS or SPC). The model system will consist of one or two water droplets surrounded by an oil phase; one droplet will be us ed for system design and simulations of equilibrium properties (surfactant distributions, interfacial properties) and two droplets will be used for non-equilibrium simulations of coalescence. The properties to be investigated are the bulk and interfacial concentration and distribution of the surfactants, the dynamic adsorption and replacement of surfactants at the interface, the compressibility of the interlayers, the surfactants' dynamic resp onse to interlayer thinning and to shear, and the effective f orce between droplets.