Improvement of macroscale properties of TiO2/cellulose acetate hybrid films by solvent vapour annealing

Abstract Two different methods were employed for the preparation of cellulose triacetate (CTA) based nanocomposites without and with poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (EPE) triblock copolymer and modified with sol-gel synthesised titanium dioxide nanoparticles (TiO2). The hybrid nanocomposites were prepared by solvent casting (SC) and solvent vapour annealing (SVA) methods. The hybrid nanocomposite films obtained by SVA presented smoother surfaces, and consequently, higher gloss values. As for transparency, only the hybrid nanocomposites prepared by SVA remained completely transparent even with high sol-gel content due to the nanostructuration of EPE triblock copolymer. Furthermore, the UV-shielding properties provided by the TiO2 nanoparticles were not modified regardless of the employed preparation method. Finally, the nanocomposites prepared by SVA presented a higher Young’s modulus and tensile strength than the SC nanocomposites. The obtained results proved the efficiency of the SVA method to control the relationship between the morphology and the final properties of the hybrid nanocomposite films leading to materials with enhanced surface, optical, and mechanical properties.