Hierarchically Porous SNP@MXene Hybrid Architectures for Ultra-Responsive Moisture Sensing and Wireless...

Enabling next-generation wearable moisture monitoring solutions requires overcoming the instability and constrained transport paths of traditional sensing materials. We present a multifunctional MXene/silica-nanoparticle (SNP@MXene) hybrid developed with a hierarchically porous structure that mitigates MXene restacking while improving water adsorption kinetics, ionic transport routes, and dielectric polarization across different humidity levels. Through the optimization of the operating frequency (100 Hz-100 kHz), the device demonstrates an extensive detection range (3%-88%RH), elevated sensitivity (62.79 nF/%RH), quick response and recovery times (830/610 ms), and stable device performance. Impedance spectroscopy, transient current analysis, and wetting kinetics demonstrate that robust interfacial coupling and maintained nanochannels inside the composite dictate humidity-dependent charge transfer and dielectric modulation. The sensor was integrated into a smart-diaper platform for real-time moisture detection, differentiating wetness states with signal amplitudes of 2.2-4.7 µF and facilitating consistent monitoring of urine occurrences. These findings confirm SNP@MXene nanohybrids as a reliable platform for wearable moisture detection, baby care monitoring, and real-time hydration assessment.