Thermal-mechanical fluctuations enhance repulsion between bimolecular layers.
Beginning with the free energy potential for long-range interactions between parallel flat sheets and the mechanical energy of bending those sheets, we have derived an upper bound for repulsion enhanced by thermal undulations of sheets in a multilamellar array. Through a self-consistent (mean-field) potential, we cover the full range of layer separations from close-in to far-apart, where the enhanced repulsion approaches the weak steric interaction derived previously by Helfrich [Helfrich, W. (1978) Z. Naturforsch. 33a, 305-315]. We have examined the effect of the fluctuation-enhanced repulsion in experimental studies of osmotic (and mechanical) compression of multilamellar lipid arrays, mechanical compression of bilayers immobilized on mica substrates, and controlled adhesion of giant bilayer membrane vesicles.
Evans
E A
EA
Parsegian
V A
VA
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007477:Ions; D008051:Lipid Bilayers; D008563:Membrane Lipids / Q000502:physiology*; D013816:Thermodynamics; D014867:Water
D007477:Ions; D008051:Lipid Bilayers; D008563:Membrane Lipids; D014867:Water