What is it about?

The vertical film drainage model is established for a liquid film containing soluble surfactants to examine the effect of the surface elasticity, solubility, and adsorption coefficient on the drainage process and identify the internal mechanism of the drainage process of a vertical film

Featured Image

Why is it important?

A mathematical model is established to investigate the gravity-driven drainage of vertical films containing a soluble surfactant by considering the coupling effect of surface elasticity, adsorption coefficient, and surfactant solubility. The lubrication theory is applied to derive the four coupled nonlinear partial differential equations describing the film thickness, surface velocity, surfactant concentration on the surface and in the bulk.


The present simulation shows that the solubility and adsorption coefficient of surfactants are significant factors affecting the film stability. In practical applications, a more stable or less stable foam can be configured as needed. For example, surfactants with a low solubility and small adsorption coefficient should be added into detergents to produce stable foams. In the aspect of food fermentation, it is necessary to reduce the production of foams as much as possible, this requires the addition of additives with a higher solubility and large adsorption coefficient.

North China Electric Power University

Read the Original

This page is a summary of: Effect of soluble surfactants on vertical liquid film drainage, Physics of Fluids, March 2019, American Institute of Physics, DOI: 10.1063/1.5085791.
You can read the full text:



The following have contributed to this page