Dipolar ordering in the ripple phases of molecular-scale models of lipid membranes.
Symmetric and asymmetric ripple phases have been observed to form in molecular dynamics simulations of a simple molecular-scale lipid model. The lipid model consists of an dipolar head group and an ellipsoidal tail. Within the limits of this model, an explanation for generalized membrane curvature is a simple mismatch in the size of the heads with the width of the molecular bodies. The persistence of a bilayer structure requires strong attractive forces between the head groups. One feature of this model is that an energetically favorable orientational ordering of the dipoles can be achieved by out-of-plane membrane corrugation. The corrugation of the surface stabilizes the long range orientational ordering for the dipoles in the head groups which then adopt a bulk anti-ferroelectric state. We observe a common feature of the corrugated dipolar membranes: the wave vectors for the surface ripples are always found to be perpendicular to the dipole director axis.
Sun
Xiuquan
X
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Gezelter
J Daniel
JD
D003198:Computer Simulation; D008051:Lipid Bilayers; D008954:Models, Biological; D008958:Models, Molecular; D008968:Molecular Conformation; D009038:Motion; D055672:Static Electricity
D008051:Lipid Bilayers