Is a Liquid Supported Amphiphile Monolayer Aptly Described as a Two-Dimensional System?: Fid-Bau Portal

Is a Liquid Supported Amphiphile Monolayer Aptly Described as a Two-Dimensional System?

Rice, S. A.

Abstract Liquid supported amphiphile monolayers have been studied for many years, yet their properties are surprisingly poorly known and little understood. For example, it is known that surface pressure (the difference between the surface tensions of the covered and clean liquid surfaces)-surface area per molecule isotherms of a liquid supported amphiphile monolayer resemble pressure-volume isotherms for a three dimensional system in that there are well defined regions of each that correspond to different phases [1]. It is generally agreed that when the surface area per molecule is very large, and the adsorbed molecules are independent of each other, the equation of state of the monolayer is like that of a gas. It is also generally agreed that when the surface density is increased a first order transition to a liquid phase occurs, unless the system temperature is less than the triple point temperature. When the surface density is increased further more phase transitions occur, first to a so-called “liquid-condensed” phase and then to a solid phase, but there is disagreement concerning the nature of the transitions [2]. Nothing is known of the intramolecular conformations or the intermolecular distribution functions in the several disordered phases. It is only recently, with the development of new experimental and theoretical techniques, that it is possible to begin to examine the relationships between molecular conformation and the structures of the different surface phases that amphiphile monolayer systems typically exhibit.