Selective crack formation on stretchable silver nano-particle based thin films for customized and integrated strain-sensing system

•Inkjet-printed Ag strain sensor for high sensitivity and stability was developed.•Brittle nature of Ag nanoparticle-based film was avoided by wrinkle structure.•Combination of crack-inducing layer and wrinkled layer was implemented.•Integrated strain-sensing system was fabricated for customizable wearable device.•Selective and precise measurement of joint flexion was possible. Wrinkle structure effectively suppresses the crack formation in a material under tensile strain, thus enabling intrinsically brittle material to be strain-tolerant. If the brittle nature of the material can be selectively engineered on the wrinkle structure, combination of mechanically different structures can be obtained within the same material. In this work, we introduce a simple and facile approach to effectively turn strain-tolerant conductive metal thin film with wrinkle structure into crack-rich thin film. The intended phenomenon was controlled by additionally inkjet-printing Ag thin film onto the wrinkle structure, and the structure and performance were also systematically optimized to enhance sensitivity and stability of the sensor. Our strategy to induce intended cracks on corrugated metal thin film enables not only to stably combine stretchable interconnectors and strain sensors but also to fabricate an integrated strain sensor system that can be custom-tailored to the subject's hand size. We believe the facile strategy will be a good step to realize an integrated strain sensor system.