Subphase pH effect on the limiting molecular area of amphiphilic β-diketones in Langmuir monolayers

Theoretical and experimental limiting molecular area values for a series of amphiphilic α- and γ-substituted β-diketones have been analyzed and compared. The investigated β-diketones exist in Langmuir monolayers as mixtures of keto and enol tautomeric forms. The ratio of the forms depends on the subphase pH and affects the shape of surface pressure–area isotherm and the experimentally determined limiting molecular area value for the monolayer.