The physics of fluids at the micro- and nanoscale
can be quite different from
macrofluidic behavior. Here we study disturbing bubbles in microchannels
found in ink jet printing. By patterning surfaces on sub-micron
scales
we try to identify individual 'nanobubbles' which may lead to
a
quantitative understanding of wall slip. These patterned surfaces
may
also serve as nucleation sites for cavitation bubbles generated
through
intense negative pressures.