PENETRATION OF AQUEOUS SURFACTANT SOLUTIONS INTO THIN HYDROPHOBIZED CAPILLARIES

Three mechanisms of the penetration of surfactant solutions into hydrophobized capillaries are possible. The first takes place at high concentrations C-0 > CMC. Spontaneous penetration corresponds to a high rate, but is limited to some finite length. The second mechanism is realized when C-0 < CMC. The rate of penetration in this case is much lower, and is controlled by the reduced concentration C-m at the meniscus. At an even lower concentration, the diffusion mechanism of penetration takes place. The rate of penetration is determined here by the surface diffusion of surfactant molecules in front of the meniscus. Forced absorption is not effective, since, as a result of adsorption, the surfactant molecules cannot reach the surface of the advanced meniscus.