Films of omega-branched fatty acids

Abstract

This investigation deals with the effect of terminal branching upon the behavior of long-chain aliphatic acids. Monomolecular layers of these compounds, spread on buffer solutions, are characterized by determination of the force/area relationship. On the basis of their minimum molecular area in condensed films, the tilt of the molecule against the surface was computed and various possibilities for the conformation of the terminal groups were evaluated. The capability of building up polylayer films on a solid surface and the character of such films reflects the shape of the molecule and its deviations from the prismatic form. A number of surface phenomena such as contact angles, surface reflection, and skeletonization by dissolving the free fatty acids in the film are treated. Although films of branched fatty acids resemble those of normal fatty acids in several points, a striking difference is revealed by their enormous surface volatility. Molecular Sublimation of branched fatty acids across blankets of stearic acid, several hundred Angström units thick, is an important manifestation of the dynamic state prevailing in crystalline polymolecular films.