Direct printing of highly sensitive, stretchable, and durable strain sensor based on silver nanoparticles/multi-walled carbon nanotubes composites

Abstract

Strain sensors with high sensitivity and large stretchability are of interest in various engineering fields. Here, directly printed stretchable strain sensors with great sensitivity and high durability was fabricated using aerodynamically focused nanomaterials (AFN) printing system. Specifically, microscale porous conductive patterns composed of silver nanoparticles (AgNPs) and multi-walled carbon nanotubes (MWCNTs) composites are printed onto polydimethylsiloxane (PDMS) for stretchable strain sensor. Printing mechanisms of AFN printing system for nanocomposites onto flexible substrates were demonstrated and experimentally validated. The printed nanocomposites strain sensor exhibits high sensitivity and wide measurable range with high mechanical stability. It shows gauge factor (GF) of 58.7, maximum strain limit of 74% and variance in peak resistance is under 5% peak during 1000 times loading-unlading life cycle evaluation test. Sensing mechanisms were analysed and explained statistically using bivariate probit models. Moreover, we also showed that sensitivity and stretchability of printed strain sensors can be controlled by regulation of AFN printing process parameter and nanocomposite composition ratio.