Surfactants in Solution pp 105-118 | Cite as
Acid — Base Properties of Liquid Dispersed Systems: Micellar Solutions, Emulsions and Microemulsions
Abstract
Potentiometry and polarography were used to investigate the acid-base properties of ordered media. Solutions of anionic (SDS), cationic (CTAB) and nonionic surfactants were investigated. One anionic (SDS) and one cationic (CTAB) surfactant stabilized emulsions were studied. A water-dodecane-pentanol - SDS raicroemulsion and a water-heptane-butanol-CTAB were also investigated for several compositions. In micellar solutions and in emulsions, it was possible to standardize and use the classical glass electrode for pH values ranging from 1 to 12. The hydrogen electrode had to be used in the microemulsion systems. The reduction of oil-soluble electrochemical probes, compounds whose reduction potential was pH-dependent, was studied using polarography. It is shown that the aqueous phase of the ordered media studied played the most important role in micellar solutions and in 0/W emulsions, as far as acid-base properties were concerned. In microemulsions, the acid-base properties of the aqueous phase were very different from those of water. The alizarin probe could be reduced at a “local” pH of about 12 when the aqueous phase pH was only 6. layer surrounding each oil-droplet in the 0/W emulsion) can be different from the aqueous phase pH. However, the difference was constant over a wide pH range. In microemulsions, the acid-base properties of the aqueous phase were different from those of water. The lower the water content, the higher the difference. The “local” pH of some microdomains seems to be very different from the pH of other ones. The reduction of Alizarin could occur at a “local” pH value of 12-13 when the aqueous phase pH was as low as 6.
Keywords
Aqueous Phase Disperse System Micellar Solution Disperse Medium Mercury ElectrodePreview
Unable to display preview. Download preview PDF.
References
- 1.A. Berthod, J. Chim. Phys., 80, 407–424 (1983).Google Scholar
- 2.J.H. Fendler and E.J. Fendler, “Catalysis in Micellar and Macromolecular Systems”, Academic Press, New York, 1975.Google Scholar
- 3.K.L. Mittal and E.J. Fendler, eds., “Solution Behavior of Surfactants”, Vol. 2, Plenum Press, New York, 1982.Google Scholar
- 4.K.L. Mittal and B. Lindman, eds, “Surfactants in Solution”, Vol. 3, Plenum Press, New York, 1984.Google Scholar
- 5.R.A. Mackay, K. Jacobson, and J. Tourian, J. Colloid Interface Sci. 76, 515–524 (1980).CrossRefGoogle Scholar
- 6.A. Honorat and P. Martinet, Electrochim. Acta, 28, 1703–1711 (1983).CrossRefGoogle Scholar
- 7.O.A. El Seoud, in “Reversed Micelles”, P.L. Luisi and B.E. Straub, eds., p. 81–93, Plenum Press, New York, 1984.Google Scholar
- 8.H. Chaimovich, R.M.V. Aleixo, I.M. Cuccovia, D. Zanette, and F.M. Quina, in Ref.3, p. 949.Google Scholar
- 9.L.S. Romsted, in Ref.4, p. 1015.Google Scholar
- 10.A. Berthod and J. Georges, J. Chim. Phys., 80, 245–249 (1983).Google Scholar
- 11.J. Georges and A. Berthod, J. Electroanal. Chem., 175, 143–152 (1984).CrossRefGoogle Scholar
- 12.A. Berthod and J. Georges, J. Colloid Interface Sci., 106, 194–202 (1985).CrossRefGoogle Scholar
- 13.H. Bahri and P. Letellier, J. Chim. phys., 82, 1010–1017 (1985).Google Scholar
- 14.A. Berthod and C. Saliba, Analusis, 13, 437–442 (1985).Google Scholar
- 15.J. Georges and S. Desmettre, J. Dispersion Sci. Technol., 7, 21–41 (1986).CrossRefGoogle Scholar
- 16.A. Berthod and C. Saliba, Analusis, 14, 414–420 (1986).Google Scholar
- 17.A.N. Frumkin and B.B. Damaskin, J. Electroanal. Chem., 3, 36–43 (1962).CrossRefGoogle Scholar
- 18.M. Clausse, J. Peyrelasse, C. Boned, J. Heil, L. Nicolas-Morgantini and A. Zradba, in Ref.4, p. 1583.Google Scholar