Stabilization of thin films of liquid hydrocarbon by alkyl chain interaction

Optically black films in aqueous solutions have been made with aliphatic hydrocarbon solutions of normal alkyl chain esters. The thickness of the hydrocarbon part of the films has been estimated from measurements of their electrical capacitance. Variation of the chain length of the hydrocarbon solvent does not, in general, influence the film thickness. On the other hand, between n-C12 and n-C22 the thickness of the hydrocarbon part of the film is apparently equal to twice the chain length of the stabilizing ester molecules. From theoretical consideration of the attractive and repulsive forces it has been shown that this result is to be expected.