Preparation of transparent hard GPTMS-Al2O3 thin films on a polycarbonate substrate.

Using polycarbonate (PC) due to its incredible properties as a suitable replacement for inorganic glasses has been increasing. Nevertheless, the low hardness limits its applications in more industries. Hence, it requires to be coated with hard anti-scratch optical coatings to overcome these limitations. In the current work, sol-gel-prepared thin films based on (3-Glycidyloxypropyl) trimethoxysilane (GPTMS)-Al2O3 were applied on PC substrates. First, silica and alumina sols were synthesized by a sol-gel process, individually. Then, the prepared sols were mixed at different ratios and dip-coated on the plasma etched pretreatment PC substrates. Curing of the samples was done in an oven at 100 °C. The produced thin films were characterized by field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Attenuated total reflectance -Fourier transform infrared spectroscopy (ATR-FTIR), and UV/Vis spectroscopy techniques. The obtained results indicated that the PC hardness increased from 6B to H by deposition of nano-hybrid coatings. After applying a nano-hybrid coating, transmittance was increased from 88 % to 91 % and the reflectance decreased from 10 % to 5 %. Sample with a 1:4 GPTMS-Al2O3 ratio showed the best results.

Fabrication of Fe-doped TiO2 nanoparticles and investigation of photocatalytic decolorization of reactive red 198 under visible light irradiation.

In this research, Fe-doped TiO2 nanoparticles with various Fe concentrations (0. 0.1, 1, 5 and 10wt%) were prepared by a sol-gel method. Then, nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis (EDX), BET surface area, photoluminescence (PL) spectroscopy and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the nano-particles was evaluated through degradation of reactive red 198 (RR 198) under UV and visible light irradiations. XRD results revealed that all samples contained only anatase phase. DRS showed that the Fe doping in the titania induced a significant red shift of the absorption edge and then the band gap energy decreased from 3 to 2.1eV. Photocatalytic results indicated that TiO2 had a highest photocatalytic decolorization of the RR 198 under UV irradiation whereas photocatalytic decolorization of the RR 198 under visible irradiation increased in the presence of Fe-doped TiO2 nanoparticles. Among the samples, Fe-1wt% doped TiO2 nanoparticles showed the highest photocatalytic decolorization of RR198 under visible light irradiation.