High‐Strength Degradable Transparent Bio‐Electronics Enabled by Confined Crystallization in Aligned Nanofibers for AI‐Assisted Motion Sensors

The severe environmental impact of conventional plastic electronics necessitates next-generation wearable devices simultaneously embodying high performance, flexibility, and sustainability. Herein, we propose a 1D nano-confined high-pressure crystallization strategy to create highly-crystalline, yet highly-transparent bio-based fiber films to meet these requirements. The bacterial copolymer poly (3-hydroxybutyrate-3-hydroxyvalerate) (PHBV)-based electrospun fibrous film, with 1D-confined oriented crystallites in the aligned nanofibers, can be transformed from opaque to transparent by heating and pressurizing and maintains its fiber morphology. The resulting film demonstrates outstanding flexibility, high optical transmittance, and significantly enhanced mechanical properties. Using this transparent fiber film as the substrate, a transparent conductive film (TCF) is produced by mechanical interlocking with silver nanowires (AgNWs), demonstrating superior performance in comprehensive metrics compared to the state-of-the-art TCFs. Critically, this TCF achieves high-fidelity capture of electromyography and electrocardiography (ECG) signals, comparable to commercial gel electrodes, while showing enhanced signal stability on sweat-soaked skin. As a proof-of-concept, a motion monitoring system is designed integrating AgNWs/PHBV-based ECG acquisition, Bluetooth transmission, and a multilayer perceptron-based classification model. Leveraging machine learning, it accurately classifies athletes' physical activity states and provides personalized training recommendations. This study may offer a new way of utilizing biological materials and inspire the development of next-generation sustainable electronics.