Thermodynamics, Kinetics and Rheology of Interfacial Layers

Thermodynamics, Kinetics and Rheology of Interfacial Layers

1. Thermodynamics of Surfactant and Protein Adsorption Layers

Thermodynamic models are developed to describe the equilibrium state of adsorption layers. The starting point is the principle of Braun-Le Chatelier. Different states of surfactant or protein molecules in an adsorption layer are assumed, controlled by the surface pressure.

Isotherms for surfactants are derived which take into consideration

  • ideal and non-ideal entropy of mixing in the adsorption layer
  • coexisting adsorption states of different molecular area
  • aggregation in the adsorption layer

For protein adsorption layers isotherms have been derived which

  • allow for different molecular surface area of an adsorbed molecule
  • yield a distribution of molecular conformation
  • give information on the adsorption layer thickness

For mixtures of surfactants first quantitative models have been published recently. These models give a very good description of experimental data, mainly in form of surface tension isotherms.

Main targets of research on this topic are

  • experiments for selected mixed surfactant systems
  • analysis of protein adsorption data at water/air and water/oil interfaces
  • performance of experiments for mixed surfactant / protein systems
  • understanding of parallels between adsorbed proteins and nano-particles

This work is performed in direct collaboration with the groups of Valentin B. Fainerman from Donetsk, Emmi Lucassen-Reynders from Vlaardingen, Eugene Aksenenko and Vladimir Kovalchuk from Kiev, Martin Leser from Lausanne.

Link to useful software tools for the analysis and prediction of the behaviour of adsorbed monolayers.

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