title: Vibrational studies and properties of hybrid inorganic-organic proton conducting membranes based on Nafion and hafnium oxide nanoparticles.
abstract: In this report, we will describe the effect of different concentrations of HfO2 nanopowders on the structure and properties of [Nafion/(HfO2)n] membranes with n = 0, 3, 5, 9, 11, 13, and 15 wt %, respectively. Films were prepared by a solvent casting procedure using HfO2 oxoclusters and Nafion. Seven new homogeneous membranes were obtained with thicknesses ranging from 200 to 350 microm. Each membrane is characterized by a rough HfO2-rich surface and a smooth Nafion-rich surface, with different physical-chemical properties. Membrane characterization was accomplished by means of thermogravimetric analysis (TGA), morphological measurements (environmental scanning electron microscopy) and vibrational spectroscopy (Fourier transform infrared attenuated total reflectance spectroscopy and Fourier transform Raman spectroscopy). These systems can be described in terms of five types of water domains, Nafion-HfO2 species with well-defined stoichiometry surrounded by Nafion and hydrated hafnia. The highest conductivity at 125 degrees C (3.2 x 10-2 S x cm(-1)) was measured on the [Nafion/(HfO2)5] film by electrical spectroscopy, with a stability range of conductivity between 5 and 115 degrees C.
authors.affiliation: Department of Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Vittadello
authors.forename: Enrico
authors.initials: E
authors.lastname: Negro
authors.forename: Sandra
authors.initials: S
authors.lastname: Lavina
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pace
authors.forename: Ahmad
authors.initials: A
authors.lastname: Safari
authors.forename: Vito
authors.initials: V
authors.lastname: Di Noto