Chitosan Thin Films Doped with Metal Oxide Nanoparticles: Production, Characterization, and Application in Supercapacitors
Chitosan, Thin films, Nanocomposites, ZnO NPs, Supercapacitors.
Polysaccharides have attracted increasing scientific interest over time, not only for their diverse applications but also for their economic viability and sustainability compared to synthetic polymers. Among these, chitosan stands out as one of the most extensively studied. Derived from the deacetylation of chitin, the second most abundant polysaccharide on the planet, chitosan possesses favorable characteristics such as biocompatibility, biodegradability, non-toxicity, and a versatile chemical structure due to the presence of hydroxyl and amine groups, making it suitable for various applications. Considering its adaptability, this study investigates the production of chitosan films, both doped and undoped, with pure zinc oxide (ZnO) nanoparticles, folic acid-doped (AF@ZnO NPs), and silver-doped (Ag@ZnO NPs), aiming to evaluate their structural, optical, and electrical properties. The efficiency of the doping and its effects at four different concentrations were analyzed, with a focus on identifying which nanocomposite has the greatest potential for application in supercapacitors. To this end, various analytical techniques were employed, including X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), UV-VIS spectroscopy, photoluminescence and FTIR spectroscopy, thermogravimetric analysis (TGA), tensile testing, and impedance measurements. The results indicated efficient doping with all variations of ZnO nanoparticles, as well as enhancement and addition of properties to the films, such as improved thermal stability, enhanced electrical properties, increased tensile strength, and good flexibility. In particular, the nanocomposites doped with Ag@ZnO NPs demonstrated characteristics suitable for use in supercapacitors, especially as part of the electrolyte separators.