MIXED MONOLAYERS OF ACYLGLYCEROLS ON SUGAR AQUEOUS-SOLUTIONS

Structural characteristics of mono- and distearin mired monolayers spr ead on aqueous solutions containing sugar (glucose or sucrose) at 0.5 mol/L were studied as a function of temperature and interfacial and su bphase compositions. The compression isotherms were obtained using an automated Langmuir-type film balance over a temperature range of 10 to 40 degrees C. The results show an expansion in the structure of the m ired monolayer with sugar in subphase. Nonideal mixing of the componen t at interface was observed with positive deviation from the additivit y rule. This fact is indicative of the presence of repulsive interacti ons between the two lipids on sugar aqueous solutions. The mixed monol ayers with a monostearin molar fraction less than 0.8 are stable from a thermodynamic point of view. Mired monolayer stability depends on mo nolayer composition, temperature, and surface pressure with different order of magnitude.