Environmentally Friendlier Printable Conductive and Piezoresistive Sensing Materials Compatible with Conformable Electronics

Flexible and conformable conductive composites have beendevelopedusing different polymers, including water-based polyvinylpyrrolidone(PVP), chemical-resistant polyvinylidene fluoride (PVDF), and elastomericstyrene-ethylene-butylene-styrene (SEBS) reinforcedwith nitrogen-doped reduced graphene oxide with suitable viscosityin composites for printable solutions with functional properties.Manufactured by screen-printing using low-toxicity solvents, leadingto more environmentally friendly conductive materials, the materialspresent an enormous step toward functional devices. The materialswere enhanced in terms of filler/binder ratio, achieving screen-printedfilms with a sheet resistance lower than R (sq) < 100 & omega;/sq. The materials are biocompatible and supportbending deformations up to 10 mm with piezoresistive performance forthe different polymers up to 100 bending cycles. The piezoresistiveperformance of the SEBS binder is greater than double that the othercomposites, with a gauge factor near 4. Thermoforming was appliedto all materials, with the PVP-based ones showing the lowest electricalresistance after the bending process. These conductive materials opena path for developing sustainable and functional devices for printableand conformable electronics.