Hematene-Reinforced Chitosan/Polyvinyl Alcohol Nanocomposite as a Bio-Derived Proton Exchange Membrane

Abstract

2D hematene nanoplatelets are obtained through a chitosan-assisted liquid-phase exfoliation process (LPE) in water and characterized using spectroscopic techniques. Subsequently, nanocomposite membranes are developed by incorporating hematene nanoplatelets at various loadings into a chitosan–polyvinyl alcohol (CS/PVA) copolymer matrix, with a parallel series prepared using a sulfonic agent at constant concentration. A comparative study is conducted to evaluate the influence of hematene and sulfonation on water uptake, swelling, ion exchange capacity (IEC), methanol permeability, mechanical behavior, dielectric properties, and proton conductivity of membranes. Hematene nanoplatelets enhance mechanical reinforcement and dielectric response, while sulfonation significantly improves IEC and methanol barrier performance. Proton conductivity increases relative to pristine polymers but did not improve with hematene addition. Overall, hematene-reinforced nanocomposite membranes demonstrate promising properties that could significantly contribute to the development of low-cost, eco-friendly, and sustainable proton exchange membrane fuel cells (PEMFCs).