Simulated phase behavior of model surfactant solutions

We performed molecular dynamics simulations in an attempt to model the phas e behavior of a nonionic surfactant. We employed a coarse-grained model, pa rametrized to yield the phase behavior of the corresponding physical system , instead of using a realistic model with its severe spatial and temporal l imitations. Within that model our surfactants are composed of chains of Len nard-Jones sites connected by harmonic springs, and the solvent is modeled as a Lennard-Jones fluid. The simulated systems comprise up to 100 000 site s with a maximum of 12 sites per surfactant molecule. We examine the effect of different conditions (temperature and concentration) and different mode l parameters (head/tail size and ratio, strength of interaction between the different sites). Our simulations show that some of the real system's char acteristics can be mirrored by the coarse-grained model, whereas some aspec ts cannot.