Influence of PEDOT:PSS coating on screen-printed textile

Abstract

This paper reports the impact of screen-printed PEDOT:PSS conductive ink on the optical properties of polyester fabric and colourimetric properties of yellow screen printing ink printed in a different number of layers. Yellow was chosen as one of four process colours which should theoretically suffer the most prominent changes from PEDOT:PSS overprinting. The study found that PEDOT:PSS ink significantly impacts the optical properties of the fabric and yellow ink, especially regarding the lightness and b-coordinate of the yellow ink. The acid treatment of samples, to increase PEDOT:PSS conductivity, also affected the optical characteristics through partial neutralization of the changes in the b-coordinate, especially when the sample was printed with a larger number of layers of the yellow ink and a smaller number of layers of PEDOT:PSS ink. Samples with two layers of yellow and one layer of PEDOT:PSS ink showed good conductivity results even without acid treatment, while the base colour appeared slightly darker. This change in the lightness can be compensated to some extent, proving that the aforementioned combination of PEDOT:PSS and base ink layers are the best when aspects, such as optical characteristics, conductivity, the complexity of production, production time, and limitations of the use of substrate materials are taken into account. This study provides useful insights for optimizing the printing process of PEDOT:PSS conductive inks over screen printed fabrics for various applications, including wearable electronics and smart textiles.