Air-grid surface patterning provided by superhydrophobic surfaces.

Recently, several unique studies on surface patterning have been developed based on superhydrophobic surfaces, where air was introduced as the separating barrier for the surface pattern. This new type of surface patterning approach is called "air-grid surface patterning." Traditional technologies of surface patterning always utilize the solid or liquid phase as the separating barrier, for example, a 2D chemical molecular barrier in soft lithography, a 3D solid barrier in photolithography, or a liquid barrier in microfluidic, laminar flow patterning methods. These recent studies reveal that air can act as a gas-phase separating barrier. This concept is expected to open up a new branch of applications of superhydrophobic surfaces, and it exhibits promising potential for functional micropatterning of various materials, from nanomaterials to crystals to cells.