Vanadium Oxide-PANI Nanocomposite-Based Macroscopic Fibers: 1D Alcohol Sensors Bearing Enhanced Toughness
Résumé
For the first time, using an extrusion process, macroscopic composite poly-vinyl alcohol(PVA)/polyaniline (PANI)-V2O5 fibers have been generated. Besides the extrusion process itself, this is certainly the first redox reaction addressed while performing an extrusion shaping process. The as-synthesized fibers have been characterized at different length scales, revealing at the mesoscale a 30° preferential orientation of the nanoribbons subunits toward the macroscopic fiber main axis. At the microscopic length scale, despite a semiamorphous nature, electron spin resonance (ESR) spectroscopy has been employed to reveal partial reduction of V5+ species to V4+ ones, where the paramagnetic species local environment has been found to be close to hydrated vanadium oxide xerogels. Concerning the organic counterpart, the aniline is oxidized into poly aniline when considering both the fibers characterization through ESR and Fourier transformed infrared (FTIR) spectroscopy and the well-known strongly oxidizing character of V5+ species toward aniline. These new PVA/PANI-V2O5 fibers are cycling when sensing alcoholic vapors while offering a good selectivity. The addressed sensitivity allows sensing 5 ppm of ethanol within 3-5 s at 42 °C. Beyond, the as-synthesized PVA/PANI-V2O5 macroscopic fibers possess a toughness of 12 J g-1, a value that has been increased by more than 120 times when compared with nanoporous inorganic fibers.