The surface pressure (p) vs. area isotherms (a) of polyoxyethylated isooctylphenols (Triton X 100 and Triton X 305), polyoxyethylene-polyoxypropylene polyols (L61 and F68), and polypropylene glycol and their binary mixtures on the surface of 40% NaNO3 aqueous solution were determine at 20? The experimental p-a curves of mixed monolayers indicated some different kinds of deviations from calculated average curves based on simple additivity. The results were interpreted in terms of the thermal motions of hydrocarbon chains and of polyoxypropylene chains if they had been squeezed out of the water surface, and a model which permitted the polyoxyethylene chain to partly lie in the interface and partly penetrate the water phase. The anal. of the compression curves of the mixed monolayers suggested that the 2 components were miscible with each other and formed 2-dimensional solns. not far from ideal.

Key words: PHENOL, COPOLYMERS, POLYETHYLENE OXIDE, METHYLOXIRANE, THIN FILMS, HIGHPOLYMER, POLYETHER, OCTANE P, NON IONIC SURFACTANTS, ETHYLENE OXIDE