Electrical Double Layer and Phospholipid Membranes. Aspects of Interface Water Structure*

It is inferred that the formation of an electrical double layer in phospholipid membranes is affected by the modified water. structure at the membrane/water interface. Theoretical evidence is presented indicating a decrease in the number density of water hydrogen bonds and the appearance of a layer of spontaneously polarized water at the solid/water interface which are the eonsequence of the orientational properties of the water structure and the asymmetric structure of the water molecule respectively. Consequences of such modifications of water structure are discussed on the basis of simple models regarding ion distribution at the interface, effect on the phospholipid chain melting phase transition temperature and the membrane-membrane interaction.