Shear-assisted laser transfer of metal nanoparticle ink to stretchable substrate

Abstract

Among the leading technologies, the wearable medical field and the development of robotics are increasing the demand for precision measurements of robot movements or biometric information. In this study, we conducted a study to manufacture highly sensitive sensor on PDMS that could be attached in necessary. Selective laser sintering of metal nanoparticle ink is an attractive technology for the creation of metal layers at the microscale without any vacuum deposition process, yet its application to elastomer substrates have remained a highly challenging task. To address this issue, we introduced the shear-assisted laser transfer of metal nanoparticle ink by utilizing the difference in thermal expansion coefficients between the elastomer and the target metal electrode. The laser was focused and scanned across the absorbing metal nanoparticle ink layer that was in conformal contact with the elastomer with a high thermal expansion coefficient. The resultant shear stress at the interface facilitates the selective transfer of the sintered metal nanoparticle layer. As a result, we confirmed that the constructed crack-based sensor works at 0.3% strain condition which could endure several times of same measurement.