蚊子腿表面多级微纳结构的超疏水特性
摘要
Mosquitoes are a type of amphibian insects with remarkable ability to walk freely, lay eggs and safely take off or land on the water surface without drowning. This article reports the water repellency mechanism of mosquito legs. The maximal supporting force of a single hind leg against water surprisingly reaches up to 600 μN, over twenty times the total body weight of this insect. While for the artificial leg made with the wire which has the same diameter, shape and structure to the mosquito leg, the supporting force is only 85 μN, far less than the value of mosquito leg. Scanning electron microscope (SEM) observations reveal the uniquely hierarchical micro-nano structure on the legs, consisting of numerous oriented ten-micro scales with uniform sub-micro longitudinal ridges and nanometer cross ribs. The surface of mosquito leg has superior water repellency, and its static contact angle is about 153°. We theoretically demonstrate that the hierarchical micro-nano structure on the surface of the mosquito leg renders such superior water repellency and high water-supporting force. This finding might be helpful in the design of innovative non-wetting materials.