Reaction of Stearic Acid Monolayers with Copper and Cuprous Oxide

Abstract

THE interesting results on partial reaction of the monolayer quoted by Dobry and Mahncke are of general interest and do in fact support the earlier observations of Bowden and Moore¹. Even allowing for the factor of 4, they found that with copper surfaces immersed in a benzene solution of stearic acid the initial reaction was very slow, and after an immersion time of 5 min. considerably less than a single monolayer of soap was formed (see their paper, footnote p. 904). After prolonged immersion, chemical attack was quite heavy and corresponded to the reaction of several molecular layers. Results of this type obtained with layers adsorbed from solution are probably more significant than those obtained with layers deposited from the Langmuir trough. The latter are often unstable and tend to collapse; they appear to form bridges over the surface irregularities so that the area of molecular contact may be considerably smaller than the area of coverage. With layers adsorbed from solution this is not so, though as Daniel² and Hirst and Lancaster³ have pointed out, dilute solutions themselves may give less than a complete adsorbed monolayer.