Colloid and Polymer Science

, Volume 282, Issue 10, pp 1169–1173

Temperature dependence of second critical micelle concentration of dodecyldimethylbenzylammonium bromide in aqueous solution

  • A. González-Pérez
  • J. Czapkiewicz
  • J. M. Ruso
  • J. R. Rodríguez
Original Contribution

DOI: 10.1007/s00396-004-1053-z

Cite this article as:
González-Pérez, A., Czapkiewicz, J., Ruso, J.M. et al. Colloid Polym Sci (2004) 282: 1169. doi:10.1007/s00396-004-1053-z

Abstract

The specific conductivity of dodecyldimethylbenzylammonium bromide (C12BBr) in aqueous solutions, in the temperature range of 15 to 40 °C, has been measured as a function of molality. The two breaks which were found on the conductivity against molality plots were attributed to the critical micelle concentration, cmc, and second critical micelle concentration, 2nd cmc, respectively. The ratio of the slopes, S, of the three linear fragments on the plots, S2/S1 and S3/S1, was attributed to the degree of ionization of the micelles at cmc and 2nd cmc respectively. It was shown that the values of the 2nd cmc estimated above 27 °C are only apparent due to thermal disintegration of the micelles. In the temperature range of 15 to 27 °C, the values of the 2nd cmc increase gradually and the plot of the 2nd cmc against temperature is concave. The ratio of 2nd cmc/cmc for C12BBr at 25 °C amounts to 15 and appears to be high compared to the literature values for other surfactants. For comparative purposes the cmc and 2nd cmc values were also estimated conductometrically for decyldimethylbenzylammonium bromide (C10BBr) at 25 °C. The 2nd cmc value for this surfactant is higher compared to the value for the C12 homologue by a factor of 2.6.The standard Gibbs free energies of micellization at cmc and at the 2nd cmc were estimated from the experimental data for both surfactants at 25 °C.

Keywords

Decyl- and dodecyldimethylbenzylammonium bromide Second critical micelle concentration Conductivity Temperature dependence 

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • A. González-Pérez
    • 1
  • J. Czapkiewicz
    • 2
  • J. M. Ruso
    • 3
  • J. R. Rodríguez
    • 1
  1. 1.Grupo de Ciencia y Tecnología de Coloides, Departamento de Física de la Materia Condensada, Facultad de FísicaUniversidad de Santiago de CompostelaSantiago de CompostelaSpain
  2. 2.Faculty of ChemistryJagiellonian UniversityKrakówPoland
  3. 3.Grupo de Biofísica e Interfases, Departamento de Física Aplicada, Facultad de FísicaUniversidad de Santiago de CompostelaSantiago de CompostelaSpain

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