Synthesis of chitosan/polypyrrole membranes for application in PEM fuel cells

Abstract

This work describes the synthesis and characterization of chitosan/polypyrrole membranes, obtained by plasma-assisted glow discharge doping, to evaluate their suitability as polymer electrolyte membranes for fuel cell applications. Chitosan serves as a hydrophilic matrix and structural support that facilitates proton transport, while polypyrrole improves the system’s functional properties. The membranes were functionalized by sulfonation, which allowed the incorporation of –SO3H groups, as confirmed by Fourier transform infrared spectroscopy. Scanning electron microscopy revealed the incorporation and distribution of polypyrrole within the polymer matrix, as well as the morphological changes induced by sulfonation. Water absorption decreased as polypyrrole concentration increased. However, sulfonation promoted an increase in water absorption, likely associated with the presence of hydrophilic sulfonate groups that favor water retention. Open-circuit voltage measurements showed values between 0.3 and 0.7 V, comparable to those reported for polymeric membranes under similar experimental conditions. Overall, the results indicate that combining chitosan, polypyrrole, and sulfonation enables the development of membranes with functional properties, supporting further evaluation as a promising and sustainable alternative for fuel cell applications.