Ultrathin bending sensor with ultrahigh robustness and reliability for robotic applications

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Soft bending sensors offer high sensitivity and a large deformation range, making them ideal for robotics and healthcare. However, existing sensors made from organic materials often fail under large tensile stresses and long-term bending, limiting their real-world applications. This paper presents the 100,000+ cycle-reliable bending sensor (100k+ CRBS), which leverages the flexibility and elastic response of an ultrathin piezoresistive silicon gauge integrated with highly resilient polyimide film by the water vapor plasma-assisted bonding method for both high robustness and reliability. The 100k+ CRBS endured over 100,000 bending cycles at a radius of 5 mm. Additionally, it achieved a remarkable minimum bending radius of 0.4 mm. It also exhibited a mechanical limit of 300 MPa, while maintaining stable operation below 94 MPa (<3% strain). These features enable precision motion capture in demanding applications including human–machine interaction, healthcare and rehabilitation, and smart industry and automation.