KINETICS OF THE SURFACE-TENSION OF MICELLAR SOLUTIONS - COMPARISON OFDIFFERENT EXPERIMENTAL-TECHNIQUES

The kinetics of the surface tension of micellar solutions of nonionic surfactant Triton X-100 is measured experimentally by means of three d ifferent techniques: oscillating jet, maximum bubble pressure and incl ined plate. They allow to study the micellization kinetics at various time scales (from a few milliseconds to a few seconds) in fairly large concentration region up to 50 times CMC. The experimental data are sa tisfactorily explained by a theoretical model accounting for the kinet ics of micellization, diffusion of surfactant species and expansion of the bubble interface. By this model are computed the characteristic t imes of diffusion and micellization, which are of comparable magnitude (about 5 to 200 ms), and the Gibbs' elasticity. The micellization tim e constant corresponds to the slow relaxation process known to coincid e with the disintegration of micelles. Comparing our data with other d ata from literature one can conclude that more realistic information f or the micellization kinetics is obtained by the maximum bubble pressu re and the oscillating jet method. The inclined plate seems too slow t o measure the relaxation processes in micellar solutions of this surfa ctant.