Washable and Durable Electronic Textiles Based on Polypyrrole-Coated Knitted Fabrics

Abstract This study investigated the functionalization of commercial cotton (CO) and viscose (CV) weft knitted fabrics with polypyrrole (PPy) through in situ polymerization to develop electrically conductive textiles for wearable electronics. The influence of substrate characteristics on coating formation, electrical conductivity, thermal behavior, and washing fastness was evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and electrical conductivity measurements. The PPy coating resulted in mass gains of 14.85 ± 2.4% and 13.82 ± 2.5% for CO and CV knitted fabrics, respectively. Electrical conductivity reached 5.57 × 10 −3 S cm −1 for CO/PPy and 2.91 × 10 −3 S cm −1 for CV/PPy, indicating semiconducting behavior. SEM analysis revealed a homogeneous PPy deposition on both substrates, although more pronounced polymer agglomerates were observed on CV fibers. FTIR results indicated physicochemical interactions between PPy and cellulosic fibers, while thermal analysis showed modifications in the thermal behavior of the coated fabrics, particularly for CO. Washing durability was assessed over 10 washing cycles. Both conductive textiles exhibited low mass losses (< 0.35%), demonstrating good coating adhesion. However, conductivity retention was strongly influenced by the substrate. After 10 washing cycles, CO/PPy maintained a conductivity of 1.94 × 10 −3 S cm −1 , whereas CV/PPy showed a reduction of approximately two orders of magnitude. These findings indicate that fiber morphology, knitted pattern, and coating distribution significantly affect the formation and stability of conductive pathways. Overall, the results demonstrate the potential of PPy-coated knitted fabrics as durable and washable conductive textiles for wearable electronic applications.