Molecular dynamics simulation of micelle formation in amphiphilic solution

The micelle formation in amphiphilic solution is investigated by molecular dynamics (MD) simulation of coarse-grained rigid amphiphiles with explicit solvent molecules. In our simulation model, the intensity of the hydrophilic interaction and the hydrophobic interaction can be varied independently. Our simulations show that various kinds of micellar structures are formed at a lower temperature by quenching from a random configuration of amphiphilic molecules in solution at a higher temperature. The micellar shape changes from a disc (bilayer) into a cylinder and then into a sphere as the intensity of the hydrophilic interaction increases. It is also found that the micelle formation proceeds in a stepwise fashion through the coalescence of smaller micelles. From the analysis of the orientational order for the amphiphilic molecules, it is concluded that the orientational order parameters can be used to distinguish the micellar shapes clearly.