Fern-Leaf-Inspired Multifunctional Flexible Strain Sensors for Motion Monitoring, Information Communication and...

Flexible sensors play a crucial role in various emerging high-tech fields including electronic technology, information industry, and bioengineering. However, achieving excellent comprehensive performances through optimum structural designs remains a great challenge. Here, a facile technique is proposed to prepare high-performance flexible strain sensors based on fern-leaf-inspired hierarchical structures including primary, secondary, tertiary veins, and corrugated surfaces. The primary vein with a deep W-shaped groove plays a critical role in optimizing sensing performances by the formation of staggered cracks and establishment of serpentine conductive paths. This unique sensing mechanism endows the sensor with excellent comprehensive performances including high sensitivity (up to 20940), low detection limit (0.06%), wide detection range (40%), fast response/recovery speed (83/92 ms), good cyclic stability (20000 cycles), and outstanding bidirectional bending capacity. As a demonstration of applications, the fern-leaf-inspired sensor has been used for human motion monitoring, Morse code expressing, information encryption, machine learning-assisted bending recognition, and health alert. This innovative design not only shows the application prospect of biomimetic sensors in the fields of health management and information communication, but also provides a new idea for future intelligent interactive systems.