Bioinspired Anisotropic Slippery Cilia for Stiffness-Controllable Bubble Transport

Bubbles
play a crucial role in multidisciplinary industrial applications, e.g., heat transfer and mass transfer. However, existing
methods to manipulate bubbles still face many challenges, such as
buoyancy inhibition, hydrostatic pressure, gas dissolving, easy deformability,
and so on. To circumvent these constraints, here we develop a bioinspired
anisotropic slippery cilia surface to achieve an elegant bubble transport
by tuning its elastic modulus, which results from the different contacts
of bubbles with cilia, i.e., soft cilia will be easily
bent by the bubble motion, while hard cilia will pierce into the bubble,
consequently leading to the asymmetric three-phase contact line and
resistance force. Moreover, a real-time and arbitrarily directional
bubble manipulation is also demonstrated by applying an external magnetic
field, enabling the scalable operation of bubbles in a remote manner.
Our work exhibits a strategy of regulating bubble behavior smartly,
which will update a wide range of gas-related sciences or technologies
including gas evolution reactions, heat transfer, microfluidics, and
so on.