A Theory of Phase Transitions and Phase Diagrams for One- and Two- Component Phospholipid Bilayers

A statistical mechanical partition function for phospholipid bilayers is constructed to obtain a theoretical description of the chain melting phase transition in lipid bilayer membranes and of the phase diagrams for two-component bilayers. In addition to providing an accurate representation of the transition temperatures and enthalpies of one-component bilayers composed of 1,2-diacylphosphatidylcholines, the theory can also account for the shapes of the phase diagrams observed for bilayers which are binary mixtures of these compounds with two different hydrocarbon chain lengths.