BINARY MIXED MONOLAYERS OF POLYVINYL STEARATE AND SIMPLE LONG-CHAIN COMPOUNDS AT THE AIR-WATER-INTERFACE

Binary mixed monolayers of poly(vinyl stearate) with 1-hexadecanol, 1-octadecanol, and stearic acid at the air/water interface were studied using pressure-area isotherms and resistance to water evaporation. All of these two-dimensional polymer solutions were homogeneous, but showed marked deviations from ideality. Negative values of excess free energy of mixing (ΔGex) indicated condensation effect and the increase in excess free energy of activation for water evaporation (ΔGex‡) was closely correlated with the decrease in ΔGex. These behaviors are attributed to tight packing of the long-chain alcohols or acid within the free area of the comb-like polymer. © 1979.