Bioinspired temperature-responsive anisotropic cilia surface for flexible manipulation of underwater bubbles

Underwater bubble manipulation has gradually drawn worldwide attention to the tremendous academic and industrial fields such as water electrolysis, heat transfer, and mineral flotation. To accurately manipulate the motion of the underwater bubble, buoyancy or Laplace gradient forces arising from the surface geometry are widely applied by employing asymmetric surface. However, these strategies suffer from limited manipulation flexibility and restrains the applicability to many fields. Herein, a temperature-responsive anisotropic cilia surface (TRAS) is introduced to achieve bidirectional long-range bubble transport. Relying on the temperature-responsive property of the TRAS, elastic modulus and stiffness of the TRAS surface can be flexibly regulated. This unique characteristic of TRAS enables the bidirectional transport of underwater bubbles by modulating the asymmetric three-phase contact line and viscous resistance. The temperature-responsive strategy presents promising applications in heat transfer, electrochemistry, and so on.