2004/08/31 by R. Elliott, Richard Elliott, K. B. Katsov +4 · 1 citation
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · Physics and Astronomy · #Lipid Membrane Structure and Behavior #Nanopore and Nanochannel Transport Studies #Surfactants and Colloidal Systems #physics.bio-ph
paper · pdf · doi:10.1063/1.1836753
29 pages, 4 figures, 1 table. revised version
openalex publication_date 2005/01/07 · arxiv created 2005/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A molecular model is proposed of a bilayer consisting of fully saturated dipalmitoylphosphatidylcholine (DPPC) and mono-unsaturated dioleoylphosphatidylcholine (DOPC). The model not only encompasses the constant density within the hydrophobic core of the bilayer, but also the tendency of chain segments to align. It is solved within self-consistent field theory. A model bilayer of DPPC undergoes a main-chain transition to a gel phase, while a bilayer of DOPC does not do so above zero degrees centigrade because of the double bond which disrupts order. We examine structural and thermodynamic properties of these membranes and find our results in reasonable accord with experiment. In particular, order-parameter profiles are in good agreement with NMR experiments. A phase diagram is obtained for mixtures of these lipids in a membrane at zero tension. The system undergoes phase separation below the main-chain transition temperature of the saturated lipid. Extensions to the ternary DPPC, DOPC, and cholesterol system are outlined.