On the statistical thermodynamics of membrane formation.

Modifying a procedure developed by Scheutjens and Fleer (J. Phys. Chem. 83 (1979) 1619; J. Phys. Chem. 84 (1980) 178) to describe adsorption of polymers, a lattice theory is proposed to formulate the formation and properties of amphiphilic bilayer membranes. In this theory individual conformations are distinguished and lateral interactions are taken into account in a Flory-Huggins approximation. Probability distributions of head, tail and solvent segments are computed and it is shown that they are not narrow, i.e., membrane properties are subject to considerable fluctuations. The average concentration of the water in the hydrophobic core is nonzero. Various extensions, consequences and applications are proposed.