Knowledge Bank

The phase diagrams of lipid-water systems are extremely complex. Nonetheless, structural characterization of these phases is of interest in the biophysical chemistry of membranes. It will be shown that Raman spectroscopy is a sensitive probe of the structure of these phases. Three distinct (from the viewpoint of the phase rule) examples will be discussed: 1. Pure-lipid-water gels at constant composition with variable temperature; 2. Variable composition mixtures of two lipids plus water at constant temperature and constant percent water; 3. Pure lipid plus water in constant composition ratio, plus either variable amounts of solute $(CHCl3,CCl4,benzene)$ at constant temperature or constant amounts of solute at variable temperature.