Piezoresistive thin film pressure sensor based on carbon nanotube-polyimide nanocomposites

A novel ring-shaped piezoresistive pressure sensor is designed, fabricated and characterized in this paper. Carbon nanotube (CNT)-polyimide (PI) nanocomposites with different CNT concentrations are prepared in a liquid mixture as the fabrication material. The ring-shaped nanocomposite thin film device is deposited on a circular polyimide diaphragm by inkjet printing fabrication method. The drop-on demand fabrication process of the inkjet printer enables the fabrication of nanocomposite thin film in various geometries and shapes to achieve better structural compatibility with the sensor port and overall measurement accuracy. The equivalent circuit parameters of the nanocomposite thin film device are derived through electrical impedance measurement. The sensitivity of the ring-shaped CNT-PI pressure sensor is investigated, and the gauge factors under static pressure are characterized using a pressure tube. The results demonstrate that this novel ring-shaped nanocomposite thin film pressure sensor can be used for pressure measurement with easy fabrication process, excellent flexibility and high sensitivity. (C) 2019 Elsevier B.V. All rights reserved.