Phase Transitions In An Implicit Solvent Minimal Model Of Lipids: Role Of Head-Tail Size Ratio

We present Monte Carlo simulations under constant NVT conditions on a minimal three beads coarse grained implicit solvent model of lipid molecules, with the hydrophilic head represented by one bead and the hydrophobic tail represented by two beads. We consider two lipids, one with the head and tail bead sizes equal and the other with the tail beads smaller than the head. When cooled to the ambient temperature from an initial isotropic phase at high temperature, the first lipid transforms spontaneously to a lamellar phase while the second lipid transforms to a micellar phase, showing the crucial role of the head and tail size ratio on lipid phases.