Nanocomposite based on functionalized gold nanoparticles and sulfonated poly(ether ether ketone) membranes: synthesis and characterization

Gold nanoparticles, capped by 3-mercapto propane sulfonate (Au-3MPS), were synthesized inside a swollen sulfonated poly(ether ether ketone) membrane (SPEEK). The formation of the Au-3MPS nanoparticles in the swollen sPEEK membrane was observed by spectroscopic and microscopic techniques. The nanocomposite containing the gold nanoparticles grown in the sPEEK membrane, showed the plasmon resonance λmax at about 520 nm, which remained stable over a testing period of three months. The size distribution of the nanoparticles was assessed, and the sPEEK membrane roughness, both before and after the synthesis of nanoparticles, was studied by AFM. The XPS measurements confirm Au-3MPS formation in the sPEEK membrane. Moreover, AFM experiments recorded in fluid allowed the production of images of the Au-3MPSatsPEEK composite in water at different pH levels, achieving a better understanding of the membrane behavior in a water environment; the dynamic hydration process of the Au-3MPSatsPEEK membrane was investigated. These preliminary results suggest that the newly developed nanocomposite membranes could be promising materials for fuel cell applications.