A novel flexible sensor for double-parameter decoupling measurement of temperature and pressure with high sensitivity and wide range

Abstract

Multi-parameter comprehensive sensing, as a data source for measuring and evaluating the physical state of devices, has become an important direction for the development of flexible electronics. In this case, temperature and pressure are the two common physical parameters, which are usually coupled; however, it is significant but challenging to decouple them simultaneously. Herein, a flexible double-parameter sensor is proposed to realize the decoupled measurement of temperature and pressure based on the thermal-resistance effect and piezocapacitive effect, respectively. A PEDOT:PSS/MWCNT serpentine electrode was prepared via the dispensing printing process to measure temperature, while a PVA/H₃PO₄ ionic film dielectric layer was prepared on porous conductive fabric via the electrostatic spinning process to sense pressure. The advantage of the proposed sensor is that the double dielectric layer capacitance for measuring pressure has a relatively large value and is sensitive to pressure, but not temperature, achieving the direct decoupling measurement of pressure and temperature in conventional measurements. The sensor layers were innovatively designed to enable the serpentine electrode for measuring temperature to be used as an electrode in piezocapacitive sensors. Finite element analysis was conducted to compare the sensitivity of the pressure measurement, realizing the optimized sensor configuration of top piezocapacitive layer and bottom thermal-resistance layer. The designed sensor was proven to have an extremely wide measurement range and high sensitivity. In the case of temperature, it could measure the temperature range of 15–80 °C, and the sensitivity below 50 °C was as high as 0.032 °C⁻¹. In the case of pressure, a wide measurement range of 0–600 kPa was demonstrated, with an extremely high sensitivity of 1249.34 kPa⁻¹ for low-pressure measurements below 10 kPa. The above-mentioned excellent performance proves that the proposed flexible sensor has significant potential application for the simultaneous measurement of temperature and pressure.