Bicontinuous interfacially jammed emulsion jels (bijels) are new multiphase soft materials in which two interpenetrating regions of immiscible liquids are stabilized by a jammed monolayer of colloidal particles, sitting at the interface between the two liquids. Such materials were first predicted via (Lattice-Boltzmann) computer simulation and subsequently realized in the lab, with mixtures of water and lutidine (W/L) stabilized via silica colloids with near-equal affinity to both species. Bijels properties are predicted to be highly tunable in terms of the size and volume fraction of the solid particles and perhaps also their shape, say ellipsoids versus spheres, over a broad range of scales.
We plan to perform systematic studies of the morphological and mechanical properties of the bijel metastable structure, i.e. pore size and elasticity as a function of colloidal size and volume fraction. More specifically, we shall investigate the effects of the particle radius and volume fraction on the morphology, pore size distribution and resulting mechanical properties of the bijels for different types of motifs.
For many applications, say tissue engineering, it is imperative to access pore sizes above 100 µm, which appears problematic with standard bijels. This can be achieved by a variant of bijels, known as bridged bijels, in which one phase contains a network of colloidal-bridged droplets. This dual morphology results from combined spinodal decomposition and nucleation and growth in a binary mixture containing neutrally wetting colloids with selective affinity for one liquid phase. Likewise bijels, the mechanical and morphological properties of bridged-bijels are highly sensitive to the physical-chemical properties and volume fractions of the colloidal particles.