An Underwater Flow Sensor Inspired by Air-Retaining Hairs of Notonecta

This paper presents a novel design mechanism of underwater flow sensor inspired by mechanosensitive air-retaining hairs of a backswimmer (Notonecta). The flow sensor, consists of a PDMS cantilever beam, a piezoresistor with single wall carbon nanotubes (SWCNTs) and Ag nanoparticles (AgNPs) nanocomposite on the cantilever, and a superaerophilic substrate. The SWCNTs/AgNPs nanocomposite was fabricated by a direct printing process, and a gauge factor of 150 was achieved. The air-retaining structure was created by the superaerophilic surface of the substrate and the PDMS sensing cantilever. The experimental results indicated that the sensitivity of the flow sensor with air layer was about 2.4 times higher than that of the sensor without air layer.