Plasma‐Induced Wrinkle‐Crack Dual Structure for Robust Directional Strain Sensing in Dynamic Motion Perception

Flexible multi-directional sensors hold vast potential for complex application scenarios, yet creating sensitive, stable, and linear strain sensors capable of flexibly detecting multi-directional strain remains a significant challenge. Here, a plasma-induced wrinkle-crack dual structure is introduced for multi-directional force detection of high-reliability flexible strain sensors. By combining pre-stretching and oxidative plasma bombardment, a multi-layer structure exhibits film stress engineering with varying elastic moduli established on the surface of the elastomer. The rigid silicon oxide hardened layer induces shear film stress at the pre-stretched interface. Periodic wrinkles are generated upon release from pre-stretching, which not only suppresses crack propagation but also significantly enhances the linearity between the signal and applied force, thanks to the conductive network's wrinkles. By adjusting the direction of pre-stretching under plasma treatment, the morphology and orientation of the wrinkles on the conductive sensitive layer can be effectively controlled. The coexisting parallel wrinkle and perpendicular crack structures impart anisotropic properties, significantly improving the sensor's directional detection capabilities. With a high gauge factor (GF = 454), excellent cyclic durability (over 100 000 cycles), and multi-directional force detection capability, this sensor demonstrates promising applications in wearable electronics and robot motion detection, positioning it as a next-generation flexible strain sensor.