A Flexible Pressure/Temperature Sensor Based on CNTs/PEDOT:PSS/PVA/Silicone Rubber Composites for Motion Recognition and Battery Temperature Monitoring

Abstract

Simultaneous sensing of pressure and temperature is essential for next-generation flexible electronics and electronic skin. However, signal crosstalk between different stimuli and the reliance on complex signal-processing circuits remain major challenges in multifunctional sensor design. Herein, a self-decoupled flexible pressure–temperature dual-modal sensor is developed by integrating a piezoresistive pressure-sensitive layer composed of silicone rubber (SR) and multiwalled carbon nanotubes (MWCNTs) with a thermoelectric temperature-sensitive layer based on poly(vinyl alcohol) (PVA) and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS). Benefiting from the physical separation of the piezoresistive and thermoelectric sensing mechanisms, pressure and temperature are independently converted into resistance and voltage signals, respectively, enabling intrinsic signal decoupling without additional signal-processing circuits or postprocessing algorithms. The sensor exhibits favorable pressure-sensing performance, including a high sensitivity of 16.999 kPa–1 (0–2.06 kPa), a wide detection range of 0–103.31 kPa, fast response/recovery times (50 ms/50 ms), and outstanding durability over 6000 loading cycles while remaining insensitive to temperature variation. Meanwhile, the thermoelectric unit exhibits a Seebeck coefficient of 1.233 μV/K, a temperature resolution of 0.5 K, and favorable linearity and output stability. Moreover, the thermoelectric output remains nearly unchanged under varying pressure conditions, while the pressure response is maintained over different temperature environments, demonstrating favorable self-decoupling capability with negligible signal crosstalk. The proposed design strategy provides a simple and reliable approach for constructing multifunctional flexible sensors and shows promising potential for battery temperature monitoring, wearable healthcare, human–machine interaction, and intelligent electronic skin.