Interactions Between Oil Droplets Probed by Force Spectroscopy with the MFP-3D AFM

colloidal particles found in emulsions is important to a range of applications from the food and pharmaceutical industries through to oil recovery and mineral flotation. The interactions which occur between emulsion droplets are of huge importance in determining the functional properties of such systems. These interactions can be modified by the adsorption at the oil-water interface of surface-active species such as small molecule surfactants, proteins or polymers. However, the physical interactions which occur between emulsified oil droplets have traditionally been a difficult area to study, with work historically being carried out on model rigid colloidal particles1. This has changed recently following the development of methods to attach oil droplets to atomic force microscope (AFM) cantilevers. These methods have demonstrated that the measurements are sensitive to the nature of the interfacial film2 and have allowed detailed study of the force interactions between single pairs of droplets3, including recent mathematical modeling4. In this application note we will illustrate the advantages of studying a real fluid droplet system, capturing effects in the AFM data which are unique to deformable particles with a mobile interfacial layer. All work for this note was performed with an MFP-3D-BIOTM AFM from Asylum Research. Interactions Between Oil Droplets Probed by Force Spectroscopy with the MFP-3D AFM