Curvature elasticity of mixed amphiphilic bilayers.
Elastic bending constants of mixed amphiphilic bilayers are calculated using a molecular approach. The free energy is expanded up to quadratic order in curvatures and compositions, choosing a flat symmetrical bilayer as the reference state. Bending constants are then calculated from the derivatives of the free energy evaluated at this reference state. Two-component bilayers are considered. As a novelty, the local compositions are allowed to fully relax upon bending so that the 2 monolayers are at chemical equilibrium with each other at every curvature. The compositional degree of freedom is shown to affect the bending constant k, but not the saddle-splay constant k. The influence on the membrane elastic properties of various chain structural features, such as length, volume, and stiffness, is investigated. This may prove useful to model mixed bilayers composed of hydrocarbon/hydrocarbon and hydrocarbon/fluorocarbon chains.
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA. alberto@purdue.edu
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Gonzalez
D045424:Complex Mixtures / Q000737:chemistry; D003198:Computer Simulation; D004548:Elasticity; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008560:Membrane Fluidity; D008567:Membranes, Artificial; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D013499:Surface Properties
D045424:Complex Mixtures; D008051:Lipid Bilayers; D008081:Liposomes; D008567:Membranes, Artificial