Molecular dynamics simulation for phase behavior of amphiphilic solution

The phase behavior of amphiphilic solution is investigated by molecular dynamics simulation of amphiphilic rigid dimers with explicit solvent molecules Our simulations show that three kinds of phases (isotropic micellar hexagonal and lamellar phases) are formed at a lower temperature by quenching from a random configuration of amphiphilic molecules in solution at a higher temperature It is ascertained that an isotropic micellar phase changes into a hexagonal phase and then into a lamellar phase as the amphiphilic concentration increases It is also found that the global orientational order parameter can be used to distinguish these three kinds of phases From the detailed analyses of the phase behavior it is concluded that the hydrophilic repulsion plays an important role in the formation of the hexagonal phase while the hydrophobic attraction plays a crucial role in the formation of the lamellar phase (C) 2010 Elsevier B V All rights reserved