High-Performance Flexible Humidity Sensor Based on MXene/Bacterial Cellulose Coated Polypropylene Non-woven Fabric

Flexible humidity sensors hold significant application value in the field of wearable health monitoring. This study presents a flexible humidity sensor based on a composite of bacterial cellulose (BC), polypropylene (PP) non-woven fabric (NWFs) and MXene (Ti ₃C ₂T _x). The sensor uses PP NWFs as the substrate, with a sensing layer formed by impregnating BC dispersion (0.25-2 mg/mL) and spraying two-dimensional MXene nanosheets (2 mg/mL), followed by vacuum drying. The results show that the sensor achieves optimal performance at a BC concentration of 0.5 mg/mL, with a response value as high as 2604.6% at 98% relative humidity, response and recovery times of 52.95 s and 9.6 s, respectively, along with good flexibility and long-term stability, maintaining high performance after 21 days of storage. The excellent humidity sensitivity is resulted from the synergistic effect between the moisture-absorbing properties of BC and the high conductivity of MXene. The developed MXene/BC/NWFs humidity sensor successfully enables monitoring of non-contact signals such as fingertip humidity and breathing patterns, and realizes intelligent prediction of respiratory signals with the assistance of a neural network algorithm, demonstrating broad application potential in wearable health monitoring and non-contact human-computer interaction systems.