Novel proton conducting core-shell PAMPS-PVBS@Fe₂TiO₅ nanoparticles as a reinforcement for SPEEK based membranes

In this study, new nanocomposite membranes from sulfonated poly (ether ether ketone) (SPEEK) and proton-conducting Fe₂TiO₅ nanoparticles are prepared by the solution casting method. Sulfonated core-shell Fe₂TiO₅ nanoparticles are synthesized by redox polymerization. Therefore, 4-Vinyl benzene sulfonate (VBS) and 2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) are grafted on the surface of nanoparticles through radical polymerization. The different amounts of hybrid nanoparticles (PAMPS@Fe₂TiO₅ and PVBS@Fe₂TiO₅) are incorporated into the SPEEK matrix. The results show higher proton conductivity for all prepared nanocomposites than that of the SPEEK membrane. Embedding the sulfonated Fe₂TiO₅ nanoparticles into the SPEEK membrane improves proton conductivity by creating the new proton conducting sites. Besides, the nanocomposite membranes showed improved mechanical and dimensional stability in comparison with that of the SPEEK membrane. Also, the membranes including 2 wt% of PAMPS@Fe₂TiO₅ and PVBS@Fe₂TiO₅ nanoparticles indicate the maximum power density of 247 mW cm^-2 and 226 mW cm^-2 at 80 °C, respectively, which is higher than that of for the pristine membrane. Our prepared membranes have the potential for application in polymer electrolyte fuel cells.