Characteristics and performance studies of a composite polymer electrolyte membrane based on chitosan/glycerol-sulfosuccinic acid modified montmorillonite clay

In this study, chitosan (CS) doped sulphosuccinic acid (SSA)-glycerol (Gly) and modified montmorillonite clay (MMT) were successfully fabricated. The membranes were prepared using the solution casting method. Analysis of morphology and topography using scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the composite membrane with 3 wt% MMT filler, namely CS/MMT-1, possessed the most adequate surface roughness compared to the other fabricated membranes. Furthermore, mechanical characterization of the CS/MMT-1 composite membrane showed that the membrane achieved satisfactory mechanical strength with a value of 39.23 MPa. Proton conductivity of the composite membranes increased as the temperature was increased. The proton conductivity of the CS/MMT-1 composite membrane increased from 1.75 × 10⁻² S cm⁻¹ at 25 °C up to 3.57 × 10⁻² S cm⁻¹ at 80 °C. The CS/MMT-1 composite membrane also exhibited a methanol permeability value that was significantly lower than that of pristine CS, namely 1.22 × 10⁻⁷ cm² s⁻¹ and 12.49 × 10⁻⁷ cm² s⁻¹, respectively. The results of this study show that the fabricated composite membrane can be used as an alternative polymer electrolyte membrane (PEM) for DMFC applications.