Bio-inspired flow sensors using carbon nanomaterials

Fish utilize neuromasts to help them detect changes in water flow, which is essential for swimming, tracking prey, and performing synchronized swimming maneuvers. The neuromasts contain a staircase of hair cells that perform this task by transforming mechanical stimulation from the flowing water to electrical impulses that ultimately are transported to the brain. Inspired by the physical structure of the hairs, flow sensors are fabricated using carbonaceous nanomaterials partially embedded in a polydimethylsiloxan (PDMS) polymer substrate, which leaves part of the nanomaterial exposed to the fluid flow. This is an effective means of sensor fabrication that prevents the carbon nanomaterial from being washed away by the flowing liquid. Different carbon materials such as long and short single walled carbon nanotubes, carbon nanohorns, peapods, and multi walled carbon nanotubes are investigated in this research. All sensors from these carbon materials performed well when fabricated using this method. Future focus of this research is to maximize electrical response by implementing different techniques, aimed at improving hydrophilicity by introducing a functional group such as siloxane (SiOH) to the sensing surface and increasing the surface area in contact between the electrodes and the sensing surface.