Abstract
pH changes as a function of concentration for sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) were observed by addition of 1 N HCl and 1 N KOH. pH values increased up to the critical micellar concentration (CMC) for the SDS/HCl system and decreased for the CTAB/KOH system. In the SDS/HCl and CTAB/KOH systems, the micellar phase had a fixed composition and was homogeneous and monodisperse above the CMC. However, in the SDS/KOH and CTAB/HCl systems, pH values increased continuously and gradually below and above the CMC, and the properties of the micellar phase changed as a function of concentration, giving rise to inhomogeneity and polydispersity.
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References
Stainsby, G., and A.E. Alexander, Factors Influencing Aggregation in Soap Solutions, Trans. Faraday Soc. 46:587–597 (1950).
Goddard, E.D., and G.C. Benson, Conductivity of Aqueous Solutions of Some Paraffin Chain Satls, Can. J. Chem. 35:986–991 (1957).
Shinoda, K., T. Nakagawa, B. Tamamushi, and T. Isemura, Colloidal Surfactants: Some Physicochemical Properties, Academic Press, New York, 1963, pp. 25–28.
Tanford, C., The Hydrophobic Effect: Formation of Micelles and Biological Membranes, 2nd edn. Wiley-Interscience, New York, 1980, pp. 63–70.
Elworthy, P.H., and K.J. Mysels, The Surface Tension of Sodium Dodecylsulfate Solutions and the Phase Separation Model of Micelle Formation, J. Colloid Interface Sci. 21:331–347 (1966).
Mukerjee, P., Ionic Partial Molal Volumes and Electrostrictions in Aqueous Solution, Adv. Colloid Interface Sci. 1:241–275 (1967).
Williams, R.J., J.N. Philips, and K.J. Mysels, The Critical Micelle Concentration of Sodium Lauryl Sulphate at 25°C, Trans. Faraday Soc. 51:728–737 (1955).
Goddard, E.D., C.A.J. Hoeve, and G.C.J. Benson, Heats of Micelle Formation of Paraffin Chain Salts in Water, J. Phys. Chem. 61:593–598 (1957).
Mysels, K.J., and L.H. Princen, Light Scattering by Some Lauryl Sulfate Solutions, J. Phys. Chem. 63:1696–1700 (1959).
Mysels, K.J., P. Mukerjee, and M. Abu-Hamdiyyah, The Activity of Association Colloids Above the Critical Micelle Concentration, J. Phys. Chem. 67:1943–1944 (1963).
Mukerjee, P., K.J. Mysels, and C.I. Dulin, Dilute Solutions of Amphipathic Ions I. Conductivity of Strong Salts and Dimerization, J. Phys. Chem. 62:1390–1396 (1958).
White, P., and G.C. Benson, The Temperature Variation of the Heat of Micellization of Potassium Octanoate in Aqueous Solutions, Trans. Faraday Soc. 55:1025–1029 (1959).
Cistola, D.P., and D.M. Small, On Micelle Formation and Phase Separation, J. Am. Chem. Soc. 112:3214–3215 (1990).
Cistola, D.P., J.A. Hamilton, and D.M. Small, Ionization and Phase Behavior of Fatty Acids in Water: Application of the Gibbs Phase Rule, Biochemistry 27:1881–1888 (1988).
Cistola, D.P., D. Atkinson, J.A. Hamilton, and D.M. Small, Phase Behavior and Bilayer Properties of Fatty Acids: Hydrated 1∶1 Acid Soaps, Biochemistry 25:2804–2812 (1986).
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Topallar, H., Karadag, B. Mechanism of micelle formation in sodium dodecyl sulfate and cetyltrimethylammonium bromide. J Surfact Deterg 1, 49–51 (1998). https://doi.org/10.1007/s11743-998-0007-5
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DOI: https://doi.org/10.1007/s11743-998-0007-5