Abstract
The UV-shielding composite films based on nanocrystalline cellulose (CNC) modified with both CeO(2) and WO(3) nanoparticles were prepared by solvent casting method. In the composites, both CeO(2) and WO(3) nanoparticles showed redox activity under UV-irradiation, and the joint effects of that metal oxides in the composite films were evidenced. The WO(3) nanoparticles provided reversible photochromic properties to the WO(3)/CNC film under UV-irradiation while CeO(2) nanoparticles inhibited the photochromic effect. The mechanism of this inhibition in the CeO(2)/WO(3)/CNC films was investigated using UV-vis and FTIR spectroscopy. The photodegradation of CNC catalyzed by CeO(2) nanoparticles inherent in CeO(2)/CNC films was prevented by the addition of WO(3) nanoparticles. The CeO(2)/CNC and CeO(2)/WO(3)/CNC films exhibited strong UV-shielding property. The synthesized photostable UV-shielding CeO(2)/WO(3)/CNC films with photochromic property which can easily be tuned by the CeO(2) to WO(3) ratio can be useful for various applications, including protection of UV-sensitive dyes and production of UV-shielding packages.