Synthesis and characterization of polymeric (PMMA-PVA) hybrid thin films doped with TiO₂ nanoparticles using dip-coating technique

We report the synthesis of hybrid thin films based on Poly(MethylMethAcrylate) (PMMA) and Poly(VinylAlcohol) (PVA), doped with different concentrations of titanium dioxide nanoparticles (TiO₂ NPs). As-prepared thin films of (PMMA-PVA) doped by TiO₂ NPs (wt.% = 2%, 4%, 8%, and 16%) are deposited on glass substrate. Transmittance (T%), reflectance (R%), absorption coefficient (α), optical constants (n and k), and optical dielectric functions (ε₁ and ε₂) are deduced using the experimental transmittance and reflectance spectra. Furthermore, a combination of classical models such as Tauc, Urbach, Spitzer-Fan, and Drude models are applied to calculate the optical and optoelectronic parameters and the energy gaps of the prepared nanocomposite thin films. The optical bandgap energy of PMMA-PVA thin film is found to be 4.101 eV. Incorporation of TiO₂ NPs into PMMA-PVA polymeric thin films leads to a decrease in the optical bandgap and thus bandgap engineering is possible. Fourier-transform infrared spectroscopy (FTIR) transmittance spectra of thin films are measured and interpreted to identify the vibrational modes. To elucidate the chemical stability, thermogravimetric (TGA) curves are measured. We found that (PMMA-PVA)/TiO₂ NPs polymeric thin films are thermally stable below 110^◦C enable them to be attractive for a wide range of optical and optoelectronic applications.