Controllable fabrication of metal microcracks on rubber by mesh-like polymer mediated electroless plating for ultrasensitive and wide-range strain sensors

Strain sensors based on crack-sensitive structures have gained attention for their exceptional sensitivity. However, the geometry of the crack structures significantly impacts the balance between sensitivity and strain range, while the controllable formation of such cracks remains a challenge, often leading to performance variations. Herein, we developed an ultrasensitive strain sensor using a mesh-like polymer-mediated electroless plating (MPMEP) strategy to construct controlled nickel microcrack structures on natural rubber (NR). Poly(acrylic acid) brushes grafted via surface-initiated ATRP on NR served as interfacial layers, ensuring consistent crack morphology. The sensor achieved a high gauge factor of 417, a wide strain range of 50 %, and rapid response/recovery times (46/58 ms), with stable performance over 10,000 cycles. Compared to existing technologies, our MPMEP strategy uniquely combines high sensitivity with scalability. Moreover, its robustness and flexibility position it for wearable applications, including real-time human motion monitoring and health management. This work addresses long-standing challenges in crack-based strain sensors, presenting a reproducible and scalable platform for next-generation flexible electronics.