Bio-Inspired Flow Sensors Fabricated From Carbon Nanomaterials

Abstract

Carbon-based flow sensors can be made by embedding carbon nanotubes (CNT) into a polymeric substrate. Specifically, when a conductive aqueous solution flows over the surface of the exposed CNT, a flow-dependent voltage is generated. The carbonaceous flow sensors fabricated in our work were all tested in salt water (5% NaCl). In order to measure the surface coverage of the CNT coated sensors, the electrical resistance across the surface of each sample was measured. Electrical Impedance Spectroscopy (EIS) measurements were also carried out in order to understand the electrical relationship between the sensor and the salt water. In order to study the surface topology and morphology of the flow sensors, scanning electron microscopy (SEM) was used. Voltage measurements of sensors with different levels of resistance were tested in varying fluid velocities. The least resistive sensor showed small, but detectable changes in voltages, while higher resistance sensors showed less response. On the other hand, the average current did not change with varying flow conditions for any of the sensors.

Recent Advances in Skin-Inspired Sensors Enabled by Nanotechnology

“…In fact, Yu et al [134] has shown that piezoelectric micro-fibers have the potential for use as real-time flow sensors. Research is ongoing for developing higher performance flow sensors and to apply these technologies for various applications [135][136][137].…”

“…Instead of using pristine nanotubes, Cao et al [141] has verified that flow sensing is possible using SWNT/PDMS composite thin films. Pinto et al [142] has also studied the flow sensing response of PDMS-based films embedded with SWNTs and single-walled nanohorns (SWNH). Electrical impedance spectroscopy has been conducted for characterizing sample response to air and fluid exposure, and small changes in sensor voltage has been measured due to varying flow conditions.…”