Fully Printed Silver‐Nanoparticle‐Based Strain Gauges with Record High Sensitivity

This paper describes a strategy to impart brittle conductive patterns composed of silver nanoparticles with high stretchability and structure‐dependent electrical characteristics. Silver nanoinks are printed on an elastomeric polyurethane acrylate substrate in the form of planar serpentine structures that can effectively mitigate strain concentration. The relative changes in resistance (∆R/R ₀) and stretchability are found to strongly depend on the serpentine radius (r) that determines the strain relieving efficiency. Features with small radius of curvature show colossal ∆R/R ₀ and hold great promise as ultrasensitive stretchable strain gauges. A record high gauge factor of 10⁷ is achieved at 12% strain with r = 200 µm. Devices with larger radius of curvature exhibit higher stretchability and much more stable conductance, thus can be used as stretchable conductors. The results demonstrate the versatile functionalities that can be acquired from conventional materials by judicious structural designs.