Multilayered Single-Walled Carbon Nanotube-Based Flexible Temperature Sensor

This article presents the development of a multilayered single-walled carbon nanotube (SWNT)-based temperature sensor fabricated using a spray coating process on a flexible polydimethylsiloxane (PDMS) substrate. The carbon nanotube (CNT)-based sensor showed negative temperature coefficient (NTC) behavior, with a decrease in resistance change as the temperature increased from 293 to 383 K. It exhibited a high temperature coefficient of resistance (TCR) at −1.99/K (295–323 K) and a response time of 2.8 s. The sensor’s flexibility was tested by varying the bending radius from 21.8 to 10.9 mm and the sensor displayed consistent performance under mechanical deformation. The uniformity, roughness, and surface morphology of the coated CNTs were measured. The sensors’ accuracy and repeatability were assessed through controlled heating and cooling cycles. The stability and reliability of the sensor are improved by optimizing the coating parameters, fabrication method, and device design. The sensor showed consistency and long-term stability demonstrating its reliability for practical applications in conformal settings. The flexible CNT sensors presented in this article offer the potential to be applied for temperature sensing in conformal and flexible fitting applications, for example, temperature detection in electric vehicle (EV) battery cells.