High-Sensitivity MXene/MWCNTs/PDMS Flexible Capacitive Sensor for Wearable Health Monitoring

With the rapid advancement of wearable electronics, this study develops a flexible capacitive pressure sensor employing an MXene/MWCNTs/PDMS composite dielectric layer for high-precision health monitoring. The synergistic integration of 2D MXene nanosheets and 1D MWCNTs within the PDMS matrix forms a 3D conductive network, which enhances dielectric properties while preserving flexibility. Utilizing R1.6 electrohydrodynamic jet-printed copper electrodes alongside spin-coated dielectric layers of 25 µm thickness, the sensor achieves an exceptional sensitivity of 0.32 kPa⁻¹, an ultra-low detection limit of 0.18 Pa, rapid response and recovery times of 40 and 55 ms respectively, and a broad sensing range spanning 0.005 to 50 kPa. SEM characterization reveals that MWCNTs bridge interlayer gaps between MXene sheets, mitigating agglomeration and facilitating efficient charge transport. The PDMS matrix imparts mechanical robustness, as demonstrated by stable sensor performance over 6000 compression cycles. Practical evaluations confirm the sensor's capability to monitor multidimensional physiological activities–including joint movements, plantar pressure, respiratory rhythms, and pulse waveforms–with signal fidelity comparable to clinical-grade devices. This work addresses the sensitivity-flexibility trade-off encountered in conventional sensors through hierarchical material design and proposes a scalable fabrication strategy suitable for next-generation wearable medical technologies.