The bijel: a bicontinuous interfacially jammed emulsion gel

The bijel is a new class of soft material comprised of two fluids arrested in a bicontinuous configuration on the mesoscale. We stabilize the fluid structure using an interfacial layer of silica particles. The particles become trapped at the liquid-liquid interface because they reduce the exposed area; this relies on the particles being partially wetted by both liquids. We use water and 2,6-lutidine which have an accessible demixing transition and the particles are silica with tuned wettability. Dispersing the particles in the mixed phase and then warming through the lower critical temperature into the demixed phase leads to our novel fluid-bicontinuous structures [1]. The two fluids of the bijel are in contact through the interstices in the particle monolayer. This, combined with the arrangement of domains, means that bijels are ideal for use as membrane contactors on the microfluidic scale.