ABSTRACT
In monolayers of amphiphilic lipids, coexisting phases tend to break up into domains that are observable using epifluorescence microscopy. A major theoretical challenge has been to understand the physical and chemical properties of these domains, their shapes and sizes as well as the kinetics of change of shape and size. This chapter outlines some of the progress that has been made in studies of the properties of domains formed in coexisting liquid phases composed of binary mixtures of phosphatidylcholines and cholesterol. The quantitative understanding of the various microscopic domain structures observable in lipid monolayers should facilitate the use of these systems for chemical and biological purposes. The shapes and sizes of lipid domains at the air-water interface are determined by two competing forces. The ability to visualize phase separations in monolayers should be an impetus for the investigation of such phase separations in bilayers and biological membranes.
