Frequency-tunable piezocapacitive PDMS/MWCNT nanocomposite stretchable sensors for sign language recognition

Stretchable electronic systems with high sensitivity, long-term stability, and tunable performance are essential for next-generation human–machine interfaces and assistive wearable technologies. Here, we introduce a frequency-tunable piezo capacitive mechanism enabled by PDMS/MWCNT composite electrodes engineered near the percolation threshold. The highly piezoresistive electrodes generate AC-voltage attenuation whose effective sensing length decreases with strain or interrogation frequency, allowing us to modulate capacitive sensitivity without changing sensor geometry. This mechanism yields ultra-stable operation under large deformation, achieving higher gauge factor at 50% strain, excellent cyclic durability (2000 cycles), and minimal signal drift (≈1.3%) over 7 days of real-world wearable testing. The nanocomposite electrodes maintain uniform microstructure and mechanical compliance, ensuring reliable performance under large deformations. Integrated into a soft smart-glove platform, the sensors achieve 94.8% real-time sign-language recognition accuracy across multiple participants. This work establishes a generalizable nanocomposite-based sensing framework and introduces frequency-tunable piezo capacitive modulation as a powerful strategy for high-fidelity wearable electronics, human–machine interaction, and assistive communication technologies.