Surface treatment strategies for improving adhesion of PEDOT:PSS coatings on aerospace fiber composites

Fiber-reinforced polymer matrix composites (FRCs) offer advantages such as high strength-to-weight ratio, low density, and cost-effectiveness. However, their limited electrical and thermal conductivity poses challenges in applications such as lightning protection, electromagnetic shielding, and radar absorption. In this study, the effect of PEDOT:PSS content as a coating on layered composites to enhance electrical conductivity and adhesion properties is systematically investigated for the first time. This study explores alternative methods to enhance conductivity, focusing on the adhesion stability of the conductive coating PEDOT:PSS on aramid, carbon, and glass FRCs. Three surface treatment methods—plasma treatment (PT), piranha solution treatment (PI), and a combination of GLYMO/APTES (GA)—were tested for their effects on surface energy and adhesion strength. FTIR spectroscopy revealed significant changes in surface bonds, indicating improved adhesion through new chemical interactions. Contact angle measurements showed improved wettability, with plasma and GA treatments yielding the best results. Peeling tests demonstrated minimal changes in electrical resistance after repeated cycles for plasma- and GA-treated surfaces, highlighting their durability. Cross-cut adhesion tests confirmed that plasma-treated surfaces exhibited the strongest adhesion. This study contributes to the understanding of surface coating techniques to enhance the electrical performance and durability of FRCs, with implications for aerospace, defense, energy, and other industries.