Zeta Potential of Air Bubbles in Solutions of Binary Mixtures of Surfactants (Monodistributed Nonionic/Anionic Surfactant Mixtures)

✍ Scribed by P. Saulnier; P. Bouriat; G. Morel; J. Lachaise; A. Graciaa

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 105 KB
• Volume: 200
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1997.5361

✦ Synopsis

used this improved instrument to determine the z potential The improved spinning tube electrophorometer is used to meaof air bubbles immersed in aqueous solutions of an anionic sure the z potential of air bubbles immersed in solutions of monosurfactant or of a nonionic surfactant (11).

distributed nonionic/anionic surfactant mixtures. z potential vari-

We have found that z potential variations reflect the kinetations over time reflect the transient regime of the adsorption of ics and subsequently the equilibrium of the adsorption of the surfactants at the bubble/solution interface; for the explored surfactant molecules on the bubbles. Surfactant and countersurfactant concentrations and the studied surfactants, they show ion adsorption appear simultaneously, and as the former is that nonionic molecules are the first to occupy the interface before substantially higher than the latter, it is generally not possible being partially moved by ionic molecules. At equilibrium, the comto distinguish each of their contributions. However, for a position of the interfacial surfactant mixture is found to be close to the composition of the surfactant mixture in solution. Within the very pure nonionic surfactant and for air bubbles immersed micellization diagram, the variation of the equilibrated z potential in a solution with a very low counterion content, these contriallows the detection of a steep change of the interfacial arrangebutions are sufficiently dissociated to produce a minimum ment of the surfactant molecules at the crossing of the critical in the variation of z potential as a function of surfactant mixed micelle concentration curve.