  We outline a concept of self-assembled soft matter devices based on
micro-fluidics, which use surfactant bilayer membranes as their main building
blocks, arrested in geometric structures provided by top-down lithography.
Membranes form spontaneously when suitable water-in-oil emulsions are forced
into micro-fluidic channels at high dispersed-phase volume fractions. They turn
out to be remarkably stable even when pumped through the micro-fluidic channel
system. Their geometric arrangement is self-assembling, driven by interfacial
energy and wetting forces. The ordered membrane arrays thus emerging can be
loaded with amphiphilic functional molecules, ion channels, or just be used as
they are, exploiting their peculiar physical properties. For wet electronic
circuitry, the aqueous droplets then serve as the 'solder points'. Furthermore,
the membranes can serve as well-controlled coupling media between chemical
processes taking place in adjacent droplets. This is shown for the well-known
Belousov-Zhabotinski reaction. Suitable channel geometries can be used to (re-)
arrange the droplets, and thereby their contents, in a controlled way by just
moving the emulsion through the device. It thereby appears feasible to
construct complex devices out of molecular-size components in a self-assembled,
but well controlled manner.
