Superhydrophobic silica films from sol-gel processing
with eutectic liquid as a templating agent were investigated.
For comparison, a micron-structured silicon surface with
pillars was also prepared. The vapor condensation results
showed that the nanorough silica surfaces from the sol-gel
processing is more stable than the micron-structured surface.
Water vapor condensation onto the surface causes a loss of
superhydrophobicity for micron-size structured surfaces.
Nanostructured surfaces demonstrated that water vapor
condensation does not cause a loss of superhydrophobicity,
despite the fact that after water condensation, hysteresis
increases. Under these circumstances, the water droplet picks
up the condensed water as it rolls off the surface, thereby
cleaning the surface by removing condensed water droplets.
After removal of the micron sized water droplets, the
hysteresis recovered to its original value. And the results of
AFM force curve with tipless probe showed the negligible
interaction force between the tip and the nanorough
superhydrophobic surfaces. Such results demonstrate the
capability of reduction of adhesion forces and capillary forces
and showed the significance of application of the films in
antistiction of MEMS devices