  We present a confocal-microscopy study of demixing and remixing in binary
liquids containing colloidal particles. First, particle-stabilized emulsions
have been fabricated by nucleation and growth of droplets upon cooling from the
single-fluid phase. We show that their stability mainly derives from
interfacial particles; the surplus of colloids in the continuous phase possibly
provides additional stability. Upon heating these emulsions, we have observed
the formation of polyhedral cellular networks of colloids, just before the
system remixes. Given a suitable liquid-liquid composition, the initial
emulsions cross the binary-liquid symmetry line due to creaming. Therefore,
upon heating, the droplets do not shrink and they remain closely packed. The
subsequent network formation relies on a delicate balance between the Laplace
pressure and the pressure due to creaming/remixing. As high concentrations of
colloids in the cell walls inhibit film thinning and rupture, the networks can
be stabilized for more than 30 minutes. This opens up an avenue for their
application in the fabrication of advanced materials.
