A comparison of self-assembly in lattice and off-lattice model amphiphile solutions

Lattice Monte Carlo and off-lattice molecular dynamics simulations of h(1)t(4) and h(4)t(1) (head/tail) amphiphile solutions have been performed as a function of surfactant concentration and temperature. The lattice and off-lattice systems exhibit quite different self-assembly behavior at equivalent thermodynamic conditions. We found that in the weakly aggregating regime (no preferred-size micelles), all models yield similar micelle size distributions at the same average aggregation number, albeit at different thermodynamic conditions (temperatures). In the strongly aggregating regime, this mapping between models (through temperature adjustment) fails, and the models exhibit qualitatively different micellization behavior. (C) 2002 American Institute of Physics.