Design and fabrication of ordered silicon micro/nano-hybrid hierarchical structures decorated by silica thin layer for superantiwetting surface

The wetting properties of micro/nano-hybrid hierarchical structures offers important applications in many fields. However, the fabrication of hierarchical micro-nanostructures still suffers the limitations of complicated fabrication process, high cost and small area. Here, we develop a novel strategy for the fabrication of uniform micro/ nano-hybrid hierarchical silicon structures by combining the photolithography, thermal de-wetting and metalassisted chemical etching (MACE). The outstanding advantage of this technique is the ability to achieve nanopatterning at the full 4 '' or 6 '' wafer scale in a very facile and affordable manner, regardless of the substrate surface topography. Moreover, nanostructures generated by this technique can be customized independently at a specific level with very high feature control. By oxidizing the structure and modifying it with specific functional groups or molecules, the wettability of the surface can be transformed from the underwater superoleophobic state with an oil contact angle (OCA) of -169 degrees to underwater superoleophilic state (an OCA of -8.4 degrees). The transition from superhydrophobic state with a water contact angle (WCA) of -175.5 degrees to quasi-superhydrophilic state (a WCA of -10.5 degrees) can also be achieved, which is highly desirable for optoelectronics, environment, and biomedicine fields.