Dielectric and optical behavior of Chitosan-PVA blend doped by various insertions of titanium dioxide and cobalt oxide prepared via laser ablation route

The polymeric nanocomposites (NCs) based on CS-PVA blend with metal oxides as fillers have opened new opportunities with flexibility and specific optical, dielectric, and electrical properties. TiO₂ and Co₃O₄ were successfully incorporated into the polymeric matrix as reinforcement and tuning agents with various concentrations. XRD confirmed the existence of the polymeric matrix, TiO₂ and Co₃O₄ phases. Scanning electron microscopy (SEM) exhibited the porous structure with average particle sizes of 0.35 and 0.14 μm for TiO₂ and Co₃O₄ respectively. Further, an absorption edge shifting is detected in the optical study, starting at 5.85 eV for the blend and declining to 1.85 eV for the CS-PVA-TiO₂-7 %Co₃O₄ NC. The refractive index gradually increases with increasing inorganic filler amount to record 2.59 for CS-PVA-TiO₂-7 %Co₃O₄ from 1.69 for pure CS-PVA. Moreover, the dielectric constant decreased as the oxide filler concentration increased. All NCs exhibiting ε′ and ε″ deteriorating performance with growing in frequency, while at higher frequencies, record a constant value. The investigated nano-composite provide a potentially valuable combination for optoelectronic applications.