Effects of the hydrophobic fluid on particle jamming in Pickering systems at air/water and oil/water interfaces

The impact of interfacial properties on emulsion stability is key to designing systems with controlled mechanical properties. Utilizing strongly adsorbed solid particles at the interface, Pickering systems are shown to enhance the stability of emulsions and foams. Many interfacial studies have characterized the interfacial effects of the aqueous fluid properties and particle chemistry on these systems. Additionally, changes in the hydrophobic fluid are shown to impact particle and surfactant behavior. In this work, the interfacial mechanical properties are characterized at fluid/fluid interfaces to determine the impact of the hydrophobic fluid on solid particle jamming. A model system of CTAB and SiO₂ complexes is used to deliver particles to a/w and o/w interfaces in controlled experiments using a microtensiometer platform. Results show that the hydrophobic phase impacts the effective areal coverage of particles at the interface. When subject to nonlinear compression cycles, interfacial jamming is impacted by particle wettability and electrostatic interactions between adsorbed particles. This work highlights how changes to the hydrophobic fluid introduce further complexities to the interfacial properties, and these results further the understanding solid particle interactions at different fluid interfaces for controlled design of Pickering systems.