Study of the Dynamic Behavior of Stearic Acid Monolayers at the Air-Water Interface in the Range of Low Surface Pressures by a Current-Measuring Technique

Abstract

We have studied the dynamic behavior of stearic acid monolayers on the surfaces of pure water and of salt solutions in the range of immeasurably low surface pressures during the course of monolayer compression, by using a current-measuring technique. For monolayers formed on the surfaces of pure water and of deionized water containing cadmium ions, displacement current was generated when the area per molecule was smaller than about 60 Ų, whereas the current was negligibly small in the range of area per molecule greater than about 60 Ų. For monolayers formed on the surface of distilled water containing aluminum ions, displacement current was generated in the entire range during the course of monolayer compression. Finally, the mechanism on the current generation observed in the present current measurement was theoretically analyzed.