Highly sensitive screen printed strain sensors on flexible substrates via ink composition optimization

Abstract

Multiple screen printed strain sensors prepared with different compositions of silver and carbon particle containing inks are evaluated in terms of resistance, strain sensitivity, response linearity, and device fabrication repeatability over ten ink compositions. This approach leads to low-cost fabrication of highly sensitive strain sensors required for large area mapping of low level strain. By varying composition of two inks having large differences in conductivity, a large strain sensitivity is achieved near the percolation threshold but not so close to percolation threshold so as to sacrifice repeatability of device fabrication. In this work, the observed changes in gauge factor and electrical resistance with ink composition are gradual thereby allowing for better manufacturing control of strain gauge sensitivity and thus repeatability of strain gauge performance for the application of interest.