We report photo-controlled water gathering on bio-inspired fibers.
We have designed a bio-inspired fiber using azobenzene (Azo)
polymer materials, with roughness and a curvature similar to the
spindle-knots of wetted spider silk. We demonstrate that the cooperation
between roughness and curvature and the photo-responsive
wettability play a key role in water gathering after Vis or UV irradiation,
which regulate effectively the separation of water droplets
away from the spindle-knots or the coalescence towards the spindleknots,
respectively. This study offers an insight into the design of
novel gradient surfaces that may drive tiny droplets to move in asdesired
directions, which could potentially be extended to the realms
of fluid-control in micro-scale engines, sub-micron masks, heat
transfer, water-collecting devices and systems.
