Colloidal Interaction at the Air–Liquid Interface

In this paper, we propose a model to analyze the stability of colloidal particles at the air–liquid interface. The proposed model for the colloidal particle interaction considers DLVO interactions and capillary, hydrophobic, and dipolar interactions between the particles. Typical values from the literature were assigned to most parameters included in the model. Numerical computation revealed the most important parameter in determining the total interaction is the density of dipoles at the external surface of the particles. We have found significant differences for the pair potential between hydrophobic and hydrophilic particles. Hydrophobic particles must aggregate in a principal minimum of the interaction potential curve while hydrophilic particles aggregate in a secondary minimum.