Kinetics of Surfactant Adsorption in a Transient Foam Body

Kinetics of Surfactant Adsorption in a Transient Foam Body 

The continuous liquid phase in a foam layer is a surfactant solution whose volume and interface vary in the course of evolution. The system evolves, its volume varies because of syneresis, and the interface area varies because of the diffusion gas exchange between the system and the ambient medium. For a system with variable volume V(t) and surface area S(t), we can write out the balance equation for the surfactant mass in the system in the form 

Taking into account relations (7.3.7) and using (7.3.11), we obtain the following equation describing the variation of the surfactant concentration  

In this process, the modulus of elasticity of the adsorption layer is also a function of time and is given by 

We point out that the elasticity of the lamella, which is the basic topological element of the foam structure separating the disperse gaseous inclusions, must be substantially larger than the elasticity of the adsorption layer. 

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