Chemical and morphological surface patterning is very common in micro
uidic devices
to control the
ow. In this project, the dynamics of water droplets moving
on a iron-doped lithium niobate (Fe:LiNbO3) crystal which has been exposed to
optical patterns produced by lenses will be studied. This optowetting technique will
exploit the photovoltaic eect of lithium niobate, that creates surface charges upon
illumination and enables the control of droplets without xed electrodes. To reduce
the friction, the crystal surfaces will be covered with a micrometric lubricant lm
(LIS) made of octadecyltrichlorosilane (OTS) impregnated with silicone oil that acts
as hydrophobic dielectric layer. The behaviour of the LIS will be investigated by
droplet sliding on glass and Fe:LiNbO3 substrates and compared with results from
literature. The interaction between charged regions at the Fe:LiNbO3 surface and
water will be proved by analyzing pendant droplets falling on the substrates due
to the dielectrophoretic force. In the nal experiments, the motion of drops with
dierent volumes on straight lines with dierent inclinations imprinted on samples
tilted at dierent angles will be observed by means of video recordings
