Microstructure of Polyfuran/Perchlorate-Doped Films by Scanning and Transmission Electron Microscopies and Electron Diffraction

Polyfuran films doped with perchlorate anions (PFu/ClO 4 ) were studied by scanning and transmission electron microscopies and electron diffraction in order to analyze their morphology and microstructure. Film generation was carried out electrochemically at constant potential, E d = 2.6 V (Ag/Ag + ), onto platinum electrodes in acetonitrile/sodium perchlorate medium. The study of the superficial films morphology revealed an ordered nodular structure in the films growth face, the nodular size depending on E d . Alignment of nodules followed a direction parallel to the substrate. Crystalline structures immersed in amorphous domains were found in planar sections and cross-sections of PFu/ClO 4 films by transmission electron microscopy and selected area micro-electron diffraction. Planar sections close to the film growth surface exhibited randomly oriented crystals, while single crystals with lamellar structures were detected in deeper layers. Electron diffraction patterns obtained in planar and transversal sections were consistent with a hexagonal unit cell: a = 0.68 nm and c = 0.62 nm, α = β = 90°, and γ = 120°. The existence of moiré patterns in planar sections confirms the laminar structure proposed for PFu/ClO 4 films.