Classification of calorimetric titration plots for alkyltrimethylammonium and alkylpyridinium cationic surfactants in aqueous solutions

Abstract

Calorimetric titration plots for deaggregation of micelles formed by alkylpyridinium and alkyltrimethylammonium surfactants are classified into three types, A, B and C, depending on the shape of the plot of the enthalpy of dilution as a function of surfactant concentration. For Type A plots the recorded heat of injection q changes sharply between two parts of the titration curve over which the recorded heats are effectively independent of the composition of the solution in the sample cell. For Type B plots, the change is less sharp and both parts of the plot show dependences of heat q on solution composition, a pattern accounted for in terms of solute–solute interactions. Type C plots are complicated, in that no sharp change in q is recorded, the complexity of the plots being accounted for in terms of micelle–monomer equilibria over a range of surfactant concentrations and related enthalpies of deaggregation.

References

1. J. K. Grime, Analytical Solution Calorimetry, Wiley, New York, 1985, ch. 6.
2. K. Bijma, J. B. F. N. Engberts, G. Haandrikman, N. M. van Os, M. J. Blandamer, M. D. Butt and P. M. Cullis, Langmuir, 1994, 10, 2578.
3. J. Bach, M. J. Blandamer, J. Burgess, P. M. Cullis, L. G. Soldi, K. Bijma, J. B. F. N. Engberts, P. A. Kooreman, A. Kacperska, K. C. Rao and M. C. S. Subha, J. Chem. Soc., Faraday Trans., 1995, 91, 1229.
4. G. S. Hartley, Trans. Faraday Soc., 1935, 31, 31.
5. G. S. Hartley, Quart. Rev., 1948, 2, 152.
6. F. M. Menger and D. W. Doll, J. Am. Chem. Soc., 1984, 106, 1109.
7. M. R. Böhmer, L. K. Koopal and J. Lyklema, J. Phys. Chem., 1991, 95, 9569.
8. M. J. Blandamer, P. M. Cullis, L. G. Soldi, J. B. F. N. Engberts, A. Kacperska, N. M. van Os and M. C. S. Subha, Adv. Colloid Interface Sci., 1995, 58, 171.
9. D. F. Evans and H. Wennerström, The Colloidal Domain, VCH, New York, 1994.
10. J. H. Clint, Surfactant Aggregation, Blackie, Glasgow, 1992.
11. Y. Moroi, Micelles, Plenum Press, New York, 1992.
12. See e.g., M. J. Blandamer, J. Burgess, J. B. F. N. Engberts and W. Blokzijl, Annu. Rep. C, 1988, Royal Society of Chemistry, London, p. 45.
13. J. Fernandez and T. H. Lilley, J. Chem. Soc., Faraday Trans., 1992, 88, 2503 and references therein.
14. N. M. van Os, G. J. Daane and G. Haandrikman, J. Colloid Interface Sci., 1991, 141, 199.
15. N. M. van Os, J. R. Haak and L. A. M. Rupert, Physico-Chemical Properties of Selected Anionic, Cationic and Non-Ionic Surfactants, Elsevier, Amsterdam, 1993.
16. L. G. Soldi, Y. Marcus, M. J. Blandamer and P. M. Cullis, J. Solution Chem., 1995, 24, 201.
17. T. Mehrian, A. de Keizer, A. J. Korteweg and J. Lyklema, Colloids Surf. A, 1993, 71, 255.
18. S. Kooreman, Ph.D. Thesis, University of Groningen, 1995.
19. J. E. Desnoyers, R. De Lisi and G. Perron, Pure Appl. Chem., 1980, 52, 433.
20. D. Schuhmann, Progr. Colloid Polym. Sci., 1989, 79, 338.
21. K. Bijma, Ph.D. Thesis, University of Groningen, 1995.