Properties and long-term behavior of nanoparticle based inkjet printed strain gauges

Abstract

Strain sensors based on the resistive principle have been developed and produced by inkjet printing of nanostructured materials. Miniaturized sensor structures with grid line widths of around 75 µm and overall dimensions of 6.7 mm × 6.4 mm were successfully realized on Polyimid foils. The influence of the surface properties and the silver nanoparticle ink on the printed strain gauges was examined. With adequate densification of the printed nanoparticle containing structures, gauge factors of around 3.9 or higher were achieved. Results of reliability tests under environmental stress showed the need for a protective coatings to ensure stable long-term behavior. With adequate coatings, stable sensors are possible under a wide range of environmental conditions, such as high temperature storage or thermal cycling.