Development of a novel highly conductive and flexible cotton yarn for wearable pH sensor technology

Abstract The simple and effective approach of “dipping and drying” cotton yarn in a dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) and multi-walled carbon nanotubes (MWCNT) resulted in the development of highly conductive and flexible cotton fibres. Subsequent polyaniline (PANi) deposition yielded electrodes with significant biocompatible and antibacterial properties that could be fabricated (alongside quasi-reference electrodes) into solid-state wearable pH sensors, which achieve rapid, selective, and Nernstian responses (-61 ± 2 mV pH −1 ) over a wide pH range (2.0–12.0), even in a pH-adjusted artificial sweat matrix. This development represents an important progression towards the realisation of real-time, on-body, wearable sensors.