Strain-responsive mercerized conductive cotton fabrics based on PEDOT:PSS/graphene

The poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) conductive polymer is well known for its high conductivity and applications in conductive synthetic textiles. However, PEDOT: PSS inks/dispersions are acidic in nature (pH < 2.0). This is detrimental for natural fibre based fabrics, like cotton, due to the significant hydrolysis-induced losses in mechanical resistance. Herein, we propose a simple alkaline pre-treatment (mercerization) of cotton fabrics to minimize PEDOT: PSS hydrolysis-induced mechanical fabric degradation. Following this, graphene nanoplatelets (GNPs) were dispersed in PEDOT: PSS solutions to produce conductive, breathable and light-weight mercerized cotton fabrics by spray coating. Due to mercerization, conducting fabrics treated with the PEDOT: PSS dispersions containing 20 wt% GNPs exhibited improved Young's modulus and maximum elongation values compared to unmercerized fabrics. Similar GNP dispersions, doped with dimethyl sulfoxide (DMSO) co-solvent, produced the best conductivity levels corresponding to sheet resistance of 25 Omega/sq. (similar to 1.6 S/cm). Fabrics displayed highly repeatable and stable response to cyclic deformation tests at 5% and 10% strain rates for up to 1000 cycles with similar to 90% viscoelastic recovery levels after cessation of the cycles. Moreover, the fabrics demonstrated strong resistance against fatigue upon repeated folding-unfolding events with pressing weight, rendering them highly suitable for applications in wearable electronics, data storage and transmission, biosensors and actuators, etc. (C) 2017 Elsevier Ltd. All rights reserved.