Physical and Chemical Parameters Affecting the Damping of Capillary Water Waves by Monomolecular Layers of Organic Materials

摘要

The wave-damping action of chemically pure, as well as naturally occurring substances, was studied under controlled laboratory conditions using mechanically generated transverse water waves. The decay constant or damping coefficient was shown to increase abruptly at film pressures of less than one dyne/cm to a maximum value and to remain relatively constant as film pressure is increased further. The onset of the damping effect was closely related to major changes in the compressibility of the adsorbed insoluble monolayer. The damping coefficient for insoluble monolayer was independent of the initial wave amplitude but was linearly dependent upon the frequency. Plots of the damping coefficient (k) versus molecular area at several frequencies indicated that the abrupt damping coefficient increase was a function of monolayer compressibility and not frequency, although k attained a higher maximum value at larger frequencies. (Author)