Authors: K.A. White, E.M. Herzig, A.B. Schofield, W.C.K. Poon, M.E. Cates, P.S. Clegg
Affilation: University of Edinburgh, United Kingdom
Pages: 657 - 660
Keywords: interface, membrane, microreactor, spinodal
The bijel is a new class of functional material comprised of two simple fluids arrested in a bicontinuous configuration. We stabilize the fluid structure using an interfacial layer of silica particles. As with colloid-stabilized emulsions, the particles segregate to the liquid-liquid interface because they reduce the surface energy. We employ silica particles where the surface properties can be precisely controlled; in this case the fluids are water and 2,6-lutidine which have an accessible demixing transition. Dispersing the particles in the mixed phase and then warming through the lower critical temperature leads to our novel fluid-bicontinuous structures. The bicontinuous morphology is due to spinodal decomposition and with the particles becoming trapped on the newly created interfaces. The resulting jammed interface is a soft solid and the size of the fluid channels can be tuned by varying the proportion of particles. The bijels are ideal for use as membrane contactors on the microfluidic scale since the channels percolate and the fluids are in contact via the interstices. There are many applications: for example solvent extraction, catalysis and analysis. In addition to introducing this novel medium we will present new results showing the diffusion of solutes between the fluid channels.