Properties of the seawater‐air interface. 2. Rates of surface film formation under steady state conditions1

The laboratory techniques of dynamic surface tension and of surface electrical potential measurements were used to determine rates of formation and of reorientation of organic surface films at the seawater‐air interface. Relaxation times of surface films were determined for three characteristic samples obtained by screen and bottle sampling in the coastal waters of the northern Adriatic area. These data were compared with those for model samples produced by spreading oleic acid and crude oil on or dissolving polyethyleneglycol and sodium dodecyl sulfate in artificial seawater. Relaxation times were in the range of 0.1–1 s for most of samples. A good representative value for field samples is 0.2 s. The temperature‐dependence (the energies of activation) for the surface film relaxation indicates that several processes control material transport toward the seawater‐air interface. The findings are interpreted as showing that an almost ever‐present organic surface film influences the mechanism and the rate of material transport across the sea‐atmosphere boundary.