The role of molecular shape in bilayer elasticity and phase behavior

The role of molecular steric interactions in bilayer phase behavior and elasticity were analyzed using a solvent-free model for amphiphilic molecules in the constant tension ensemble. The lipid length at constant temperature and surface tension were adjusted to obtain the dependence of membrane elasticity on bilayer thickness. The bilayer fluidity at various lipid lengths was quantified by analysis of a length versus temperature phase diagram at vanishing tension. It was found that the thick bilayers has lower hexatic-fluid transition temperatures than thin ones and all bilayer melt at the same projected density and bond order.