Development of the ultra-high linearity flexible sensor using CMC/MXene-regulating conductive polymer strategy through resistance-capacitance hybrid response for pressure/temperature detection.

Multifunctional temperature/pressure sensors have garnered significant research interest due to their broad applicability in wearable electronics and health monitoring. Nevertheless, most pressure sensors often exhibit pronounced nonlinear responses, primarily attributed to the pressure-dependent increase in compressive modulus. In this paper, we report a multifunctional sensor with ultra-high linearity pressure and well- temperature-sensing performance, fabricated via a facile dip-coating process. The hydrogen bonding interaction between carboxymethyl cellulose (CMC) and MXene effectively mitigates the self-stacking tendency of MXene (TiCT) nanosheets. Subsequently, the CMC-modified MXene facilitates the conformational transition of PEDOT (Poly (3,4-ethylenedioxythiophene)) chains from benzoid to quinoid structures. This synergistic effect enables the fabrication of composites with enhanced electromechanical performance. Additionally, an innovative alternating current (AC) measurement is employed to investigate the potential resistance-capacitance hybrid response within the sensors. By optimizing preparation parameters, we achieve an ultra-high linearity (R = 0.9943) across a broad detection range, alongside a well temperature sensitivity (-2.3575 %/°C). Proof-of-concept applications, including quilt slippage detection and pressure ulcer prevention, demonstrate the sensor's multifunctional capabilities. These findings highlight its potential for wearable medical devices and real-time health monitoring.