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Investigating the removal of particles from the air/water-interface – Modelling detachment forces using an energetic approach A Physicochemical and engineering aspects

Knüpfer, Paul, Fritzsche, Jörg, Leistner, Tom, Rudolph, Martin, Peuker, Urs Alexander
Colloids and surfaces 2017 v.513 pp. 215-222
compliance, deformation, hydrophilicity, hydrophobicity, models
For solid particles it is energetically favorable being situated at the interface of fluid phases and removing a particle from an interface requires a high force. The capillary force effects the particle and causes an interfacial deformation during detachment. In this study the detachment force of hydrophilic and hydrophobic particles is measured via CP-AFM. In order to calculate the detachment force, a simple analytical model is developed and compared with the classical capillary force model. The new model is grounded on an energetic approach in compliance to the interfacial deformation and wetting of the particle. A model spring is assumed for both sub-processes and the force affects onto these two springs. The calculated force in the new model referred to goes better with experimental values than the capillary force model which does not consider interfacial deformation.