Eco-friendly Flexible and Stretchable Printed Electronics based on Sustainable Elastic Substrate and Ink

Abstract

The fast-growing demand for electronics is generating a substantial amount of electronic waste, raising serious concerns about its environmental impact. Herein, disintegrable, flexible, and stretchable strain sensors and electrodes are developed by printing sustainable ink onto biodegradable elastic substrate. The substrate is made of sodium carboxymethyl cellulose (NaCMC) functionalized with glycerol to achieve high stretchability, while the ink is composed of silver nanowires (AgNWs) with NaCMC and glycerol as the binders which not only contribute to overall environmental sustainability but also enable strong bonding with the substrate. The effects of material composition of both the ink and the substrate on printability, electrical conductivity, mechanical, and electromechanical properties were thoroughly examined. The results revealed that the higher the AgNWs content, the higher the electrical conductivity attained (highest conductivity of 6.5 S/m at 80 wt.% of AgNWs). In contrast, the piezoresistive sensitivity first increases with the AgNWs content to 50 wt.% and then decreases thereafter. The printed samples display a constant change in resistance over 1000 cycles, proving their durability. Moreover, printed electronics are found to disintegrate in water at room temperature within one hour, making them an eco-friendly substitute for conventional non-biodegradable electronics. Potential of the printed samples in body motion detection, human-machine interface, and stretchable electrodes has been demonstrated, highlighting their applicability in flexible, stretchable electronics.