Liquid-free ion-conductive elastomers with bioinspired oriented structures based on bacterial cellulose for dual-mode humidity sensing and energy harvesting.

A detection system that integrates flexibility, dual-modal humidity sensing, and self-powering capability is crucial for real-time monitoring of human holistic health. However, the disordered ion transport pathway restricts the versatility and application range of liquid-free ion conductive elastomer (ICEs). This study prepared an ICE with a biomimetic-oriented structure using bacterial cellulose, in which bacterial cellulose serves as the orientation skeleton to provide a fast ion transport channel, thereby integrating bimodal humidity response and self-powering capability. The optimized transport channels imparted high ion conductivity (0.122 S m-1) to the material, which is 52.6 times higher than the control sample with disordered structure. The material exhibits an excellent elongation at break (609%) and outstanding toughness (16.05 MJ m-3). Due to the synergistic effect of the oriented structure and the hygroscopicity of bacterial cellulose, the material demonstrates excellent humidity responsiveness for respiratory monitoring and moisture-enabled electricity generation with excellent output voltage (1.02 V), power density (19.1 mW m-2), and scalability. Furthermore, the material can achieve dual-modal monitoring of voltage and resistance signals, improving the accuracy of electrical signals. This work provides an optimization strategy for developing a novel biomimetic multifunctional ICEs sensor, which facilitates health monitoring and energy harvesting.