Critical Salt Loading in Flexible Poly(vinyl alcohol) Sensors Fabricated by an Inkjet Printing and Plasma Reduction Method

We report a low-temperature inkjet printing and plasma treatment method using silver nitrate ink that allows the fabrication of conductive silver traces on poly(vinyl alcohol) (PVA) film with good fidelity and without degrading the polymer substrate. In doing so, we also identify a critical salt loading in the film that is necessary to prevent the polymer from reacting with the silver nitrate-based ink, which improves the resolution of the silver trace while simultaneously lowering its sheet resistance. Silver lines printed on PVA film using this method have sheet resistances of around 0.2 omega/ under wet/dry and stretched/unstretched conditions, while PVA films without prior treatment double in sheet resistance upon wetting or stretching the substrate. This low resistance of printed lines on salt-treated films can be preserved under multiple bending cycles of 0-90 degrees and stretching cycles of 0-6% strain if the polymer is prestretched prior to inkjet printing.

Automated summary

We present a low-temperature inkjet printing and plasma treatment method for creating conductive silver traces on PVA film, achieving good fidelity and low sheet resistance. We also identify a critical salt loading in the film that prevents the reaction between the polymer and the silver nitrate-based ink, enhancing the resolution of the silver trace.