Enhanced sensitivity and stability of wearable temperature sensors: a novel approach using inkjet printing

Abstract

This work presents a wearable temperature sensor fabricated by inkjet printing using poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) ink, with a top layer of extrusion-printed silver ink serving as electrodes, on both glass and cotton-based fabric substrates. PEDOT:PSS, a widely used conductive polymer, was selected due to its affordability, conductivity, and biocompatibility. The sensors demonstrated excellent humidity resistance with enhanced conductivity, making them ideal for wearable technology applications. The glass-based benchmark sensor exhibited a resistance change of approximately 30% across a temperature range of 23 to 40 °C, with sensitivity exceeding 1.7% per °C. In comparison, the fabric-based sensor, designed for wearable applications, showed a 20% decrease in resistance with sensitivity greater than 0.65% per °C. This represents a notable enhancement compared to values reported in the literature. Both sensors exhibited a strong linear relationship between temperature and resistance, with coefficients of determination (R²) of 0.995 and 0.779 for the glass and fabric sensors, respectively. These results highlight the potential of fabric-integrated sensors for wearable applications, offering reliable performance and temperature sensitivity comparable to those of traditional glass-based sensors.