Estimating properties of surfactant mixtures

Methods and apparatus for estimating properties of a mixture of two or more surfactant species are provided. Multiple molecular dynamics simulations of the mixture are performed, each simulation using a particular total concentration of the surfactant species and a particular ratio of the surfactant species, such that the multiple simulations cover a plurality of such total concentrations and a plurality of such ratios, each simulation being carried out above the critical micelle concentration of the simulated mixture. For each simulation, and from the results of each simulation, a distribution of each surfactant species between at least a micellar pseudo-phase and a non-micellar pseudo-phase of the mixture at the particular total concentration and particular ratio for that simulation is determined. A thermodynamic model of the mixture is then fitted to the distributions to determine fitted parameters of the thermodynamic model, and the one or more properties are estimated using the thermodynamic model and the fitted parameters. The properties may comprise the critical micelle concentration of the mixture at one or more ratios of the surfactant species. The thermodynamic model may comprise a pseudo-phase separation model.