Antifogging and icing-delay properties of composite micro- and nanostructured surfaces.

A composite micro/nanostrucutred (MN) surface was designed using poly(vinylidene difluoride) (PVDF) polymer in combination with ZnO materials via heat-pattern-transfer and crystal-growth techniques. The surface, composed of ZnO nanohairs over PVDF microratchets (i.e., ZP-MN), displays excellent antifogging and icing-delay properties. Condensed water droplets can be easily shed from the ZP-MN surface at -5 °C for ∼1600 s via a slight wind or tilting. The droplets do not completely freeze on the ZP-MN surface at -10 °C until ∼7360 s. This investigation offers a way to design a structured surface that possesses anti-icing ability, which is significant because it can be extended to fields such as microdevices, engineering systems, and engines that operate in a cold or humid environment.

Strong anti-ice ability of nanohairs over micro-ratchet structures.

A strong anti-ice property of nanohairs over micro-ratchet surfaces is observed. A long freezing delay of more than 185 min is achieved for a droplet on the nanohairs over ratchet structure with a period of ∼290 µm under -10 °C, which is attributed to the effective cooperation of the nano- and microstructures.