Phase transitions and modulated phases in lipid bilayers

We develop and analyze a continuum Landau theory for ordered chiral and achiral bilayer membranes. This theory contains couplings between tangent-plane orientational order and curvature that lead to "rippled" or Pβ′ phases with one-dimensional height modulations and to phases with two-dimensional height modulations. We calculate mean-field phase diagrams from this model.