Laser-Directed Assembly of Stretchable Strain Sensors with Tunable Performance on Complex Curved Surfaces.

Stretchable strain sensors are capable of accurately mapping deformation across object surfaces, serving as critical components in structural health monitoring and failure mitigation across diverse systems. However, the inherent geometric complexity and non-uniformity of real-world surfaces pose significant challenges to conformal sensor integration. Moreover, conventional strain sensors face inherent trade-offs among sensitivity, detection range, and tunability, limiting their adaptability in practical applications. This study introduces a laser direct writing strategy that combines material and process innovations to enable scalable fabrication of strain sensors on preformed stretchable curved surfaces. Precise control of laser-induced microstructures allows programmable tuning of electromechanical properties, enabling selective behaviors such as high linearity, strain insensitivity, or pronounced resistance changes at small strains. The resulting devices exhibit a high gauge factor of up to 106, a strain detection range exceeding 100%, a minimum detectable strain of 0.1%, and excellent linearity (correlation coefficient > 0.98) within defined operational ranges. As a proof of concept, a sensor array is implemented for strain mapping and deformation reconstruction on a hemispherical 3D stretchable substrate, demonstrating the capability of this approach for high-resolution strain monitoring on complex, non-planar geometries.