Sulfonated poly (ether sulfone) composite membranes customized with polydopamine coated molybdenum disulfide nanosheets for renewable energy devices

Abstract

Sulfonated poly (ether sulfone) (SPES) membranes are fabricated using polydopamine layered molybdenum disulfide (PDM) nanosheets. The exfoliated molybdenum disulfide (E-MoS2) nanosheets are subjected to surface coating with self-polymerization of dopamine and probed by FT-IR and EDAX analysis. Membranes are characterized by FT-IR, XRD, SEM, AFM, contact angle, water uptake, ion-exchange capacity, proton conductivity, methanol permeability, TGA, mechanical and oxidative stability. Characterization results confirmed that the SPES/PDM nanocomposite membranes are better than bare SPES and Nafion-212 membranes possibly due to the interface electrostatic attraction between amine groups (-NH2 and –NH-) of PDM with sulfonate (SO3−) group of SPES which create the strong acid-base pair. This result in the enhancement of the proton transport pathway in nanocomposite membranes and also the PDM reduces the methanol transport channels by generating the tortuous path. SPES/PDM-1 membrane exhibits the highest proton conductivity of 5.64 × 10-3 Scm-1, methanol resistivity of 2.23 × 10-8 cm2s-1 and selectivity of 22 × 104 Scm-3s. SPES/PDM membranes are displayed better thermal, mechanical and oxidative stability probably due to the uniform distribution of PDM on SPES matrix as evidenced by SEM images. Overall results confirmed that the SPES/PDM membranes will be an alternate to expensive Nafion in clean energy DMFC devices.