Crack Control in Biotemplated Gold Films for Wide‐Range, Highly Sensitive Strain Sensing

Abstract Strain sensors with high sensitivity and large sensing range have great potential in a wide range of applications. However, in the design of strain sensors, there is usually a trade‐off between sensitivity and sensing range. Herein, a crack‐based strain sensor with engineered microstructure is facilely prepared through a biotemplating method. Under large tensile strains, randomly distributed microcavities on the strain sensor surface can effectively trap and terminate propagating cracks to prevent catastrophic fracture failure. As a result, the strain sensor shows both wide sensing range (up to 80%) and high sensitivity (gauge factor = 20 at 20% strain, 350 at 80% strain). The strain sensor enables sensitive and reliable detection of both subtle human motions, including wrist pulse and throat vibration, and large motions, such as finger bending. Moreover, a multipixel strain sensor array has been fabricated and applied for both static and dynamic strain mapping. The good sensing performance, together with its easy‐fabrication process, make the biotemplated strain sensor a promising candidate for applications in e‐skins and wearable electronics.