Inkjet-Printed Flexible Strain-Gauge Sensor on Polymer Substrate: Topographical Analysis of Sensitivity

Abstract

Inkjet-printed strain gauges on flexible substrates have recently been investigated for biomedical motion detection as well as the monitoring of structural deformation. This study performed a topographical analysis of an inkjet-printed strain gauge constructed using silver conductive ink on a PET (polyethylene terephthalate) substrate. Serpentine strain-gauge sensors of various thicknesses and widths were fabricated using inkjet printing and oven sintering. The fabricated gauge sensors were attached to curved surfaces, and gauge factors ranging from 2.047 to 3.098 were recorded. We found that the cross-sectional area of the printed strain gauge was proportional to the gauge factor. The correlation was mathematically modelled as y = 0.4167ln(x) + 1.3837, for which the coefficient of determination (R2 ) was 0.8383.