Properties of the seawater-air interface. 3. The electrification and energy transfer through surface films 1 , 2

Surface tension and contactless surface potential were measured simultaneously in model systems and in samples of original seawater films from the northern Adriatic area. The films were brought into a steady state in a Langmuir trough, and the electric and nonelectric components of the total energy transferred through the film were determined from hysteresis curves of surface potential vs. area of film and of curves of surface tension vs. area. The films studied were negatively charged, but the direction of energy transfer depended on the concentration of the film-forming material and on the rate of perturbation. At low concentrations the electrical component of interfacial energy transfer is predominant, at higher concentrations the nonelectric predominates. The description of the phenomenology of film behavior indicates that the enrichment of elements in the microlayer could be influenced by the concentration of film-forming material and by rates of perturbation of the microlayer by mechanical forces.