SPREADING OF ACYLGLYCEROLS ON AQUEOUS SURFACES AT EQUILIBRIUM

The equilibrium spreading pressures (pi(e)) of monostearin, monopalmit in, monoolein, and distearin crystals sprinkled on aqueous solutions c ontaining ethanol (0, 0.1, 0.5, 1.0, and 5.0 mol/liter) and glucose, f ructose, and sucrose (0, 0.1, 0.5 mol/liter) were studied using the Wi lhelmy plate method. The experiments were carried out over a temperatu re range of 5 to 40-degrees-C. The magnitude of pi(e) depends on the l ipid, on temperature, and on subphase composition. Equilibrium spreadi ng pressure changes linearly with the temperature. The magnitude and t he slope sign of that change are dependent on the film and subphase co mpositions. Thermodynamic analysis of the spreading is consistent with the hypothesis that interactions between monolayer molecules and the solute in subphase exist. These processes must include the features of the crystal spreading, the monolayer structural characteristics, and the adjacent aqueous subphase. (C) 1994 Academic Press, Inc.