LIQUID-LIQUID IMMISCIBILITY IN LIPID MONOLAYERS

Some binary lipid mixtures form coexisting liquid phases when spread a t the air/water interface. This work describes the pressure-compositio n phase diagrams of binary mixtures of four unsaturated phosphatidylch olines with dihydrocholesterol. These four binary mixtures have critic al compositions of approximately fifty mole percent, and average criti cal exponents of 0.25 +/- 0.07. The data can also be approximated by a regular solution thermodynamic model, yielding parameters for the non -ideality of these mixtures. (C) 1997 Elsevier Science B.V.