  We propose to drive open microfluidic systems by shear in a covering fluid
layer, e.g., oil covering water-filled chemical channels. The advantages as
compared to other means of pumping are simpler forcing and prevention of
evaporation of volatile components. We calculate the expected throughput for
straight channels and show that devices can be built with off-the-shelf
technology. Molecular dynamics simulations suggest that this concept is
scalable down to the nanoscale.
