Jump to main content
Jump to site search

Issue 11, 1997
Previous Article Next Article

Effect of the surfactant concentration on the kineticstability of thin foam and emulsion films


The thinning and the lifetime of foam and emulsion films formed in a model experimental cell have been investigated. The foam films were stabilised by either sodium dodecyl sulfate or sodium dodecyl polyoxyethylene-2 sulfate. The emulsion films contained either Tween 20 or Span 20. The time of hydrodynamic drainage of the films increased linearly as the logarithm of the surfactant concentration. This linear dependence was valid whatever the type of film or surfactant and not only below the critical micelle concentration (c.m.c.) but also much above this concentration threshold. The experimental results are relevant to the hydrodynamic basis of foam and emulsion stabilisation. They are compared with the earlier hydrodynamic theories of film drainage. A reasonable, but not excellent, agreement between the experimental data and the theory could be achieved in the region below the c.m.c. of the surfactant. The data about the complex system above the c.m.c. still remain unexplained by an adequate theory. The investigation provides some guidelines for choosing the optimal type and concentration of surfactant in colloid systems of practical importance.

Back to tab navigation

Article type: Paper
DOI: 10.1039/A608305F
Citation: J. Chem. Soc., Faraday Trans., 1997,93, 2069-2075
  •   Request permissions

    Effect of the surfactant concentration on the kinetic stability of thin foam and emulsion films

    K. P. Velikov, O. D. Velev, K. G. Marinova and G. N. Constantinides, J. Chem. Soc., Faraday Trans., 1997, 93, 2069
    DOI: 10.1039/A608305F

Search articles by author