Understanding Interfacial Interactions in Bijels

Most soft materials are made by processing techniques that render their final properties a function of their process history and not just their equilibrium structure. One example is the bicontinuous interfacially jammed emulsion gels (bijels), a material with numerous potential applications. Bijels are formed when solid particles get jammed at the interface between two immiscible liquids undergoing a phase separation, kinetically arresting this system. In this work, we aim to quantitatively understand the surface energy of the fluid-fluid-particle interface and how these forces influence jamming. We adopt an approach that incorporates solid particles into a phase field model, similar to the Fluid Particle Dynamics method. This approach has many benefits, including transparent methods for calculating surface tension, particle-particle interactions, and hydrodynamic interactions in dense colloidal suspensions, and it avoids complicated and costly methods for tracking particle boundaries. Our preliminary results suggest that purely repulsive particles may not be stable enough at the fluid-fluid interface to jam, suggesting that attractive forces may be needed for bijel stability.