Monolayer phases of the fatty acids and their ethyl esters

The miscibility correspondence between water-surface monolayer phases of the fatty acids and their ethyl esters was determined. Ester phases were found corresponding to all the known phases of the acids, and vice versa, in similar relative positions of the π-T diagram. Evidence is presented for the existence of a ninth distinct miscibility category, represented by a phase in each of the pure materials, and a tenth found only in mixtures. We propose a tentative correspondence to bulk smectic miscibility categories.