Molecular simulation of self-assembly in surfactant and protein solutions

In this work we study phase and structural transitions of simple lattice models for surfactant and protein solutions using Monte Carlo simulations. An extension of the Gibbs ensemble methodology to lattice systems is proposed. This method is used with an oil/water/surfactant model due to Larson to investigate the phase diagram of an asymmetric surfactant. A partial phase diagram is given in the region of low surfactant concentration. We have also studied the structural transitions of a simple lattice model for proteins due to Dill using the Rosenbluth and Rosenbluth chain growth algorithm combined with Boltzmann weighting and multi-link additions. This simple model seems to have limitations. In particular, the unique or almost unique lowest energy states that exist for certain model proteins of moderate length approaching that found in the simplest real proteins cannot be found in feasible simulation times. These problems appear to stem from the lack of sufficient specificity in the interactions.