Studies on adsorption of natural and synthetic hymatomelanic acids at air–water and at oil–water interfaces

By utilizing a static method, based on slight modification of the Wilhelmy plate method, the interfacial properties of one natural and two synthetic hymatomelanic acids were studied at both the air–water and oil–water interfaces. On this basis their number-average molecular weights, flexibility and shape of the macromolecular chains at the interface, and the related thermodynamic parameters were evaluated.