Loading...

Nanomechanical properties of TiO2 granular thin films

Yaghoubi, H ; Sharif University of Technology | 2010

2029 Viewed
  1. Type of Document: Article
  2. DOI: 10.1021/am100455q
  3. Publisher: 2010
  4. Abstract:
  5. Post-deposition annealing effects on nanomechanical properties of granular TiO2 films on soda-lime glass substrates were studied. In particular, the effects of Na diffusion on the films' mechanical properties were examined. TiO2 photocatalyst films, 330 nm thick, were prepared by dip-coating using a TiO2 sol, and were annealed between 100 °C and 500 °C. Film's morphology, physical and nanomechanical properties were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, differential thermo-gravimetric analysis, and nanoindentation. Contrary to expectations, the maximum film hardness was achieved for 300°C annealing, with a value of 0.69 ± 0.05 GPa. Higher annealing temperatures resulted in inferior mechanical properties. No pile-up or sink-in effects were observed with minimal creep for the 300 °C annealed sample. Considerable decrease in the amount of chemisorbed water was found with increasing annealing temperature, causing gel films densification, explaining the increasing trend of hardness with annealing temperature between 100 °C and 300 °C. DTA/TGA results also confirmed the weight loss and the endothermic reaction due to desorption of chemisorbed water. Decrease in hardness above 300 °C annealing is attributed to thermal diffusion of Na ions from the glass substrate, confirmed by nanoindentation tests on TiO 2 films deposited on fused quartz, which did not exhibit hardness decrease after 300 °C annealing
  6. Keywords:
  7. Photocatalyst ; Annealed samples ; Annealing temperatures ; Berkovich indenters ; Dip coating ; Endothermic reactions ; Film hardness ; Fused quartz ; Gel films ; Glass substrates ; Granular thin films ; Nanoindentation tests ; Nanomechanical property ; Photocatalyst film ; Pile-ups ; Post deposition annealing ; Self-cleaning ; Sink-in ; Soda lime glass substrate ; TiO ; Weight loss ; Atomic force microscopy ; Atomic spectroscopy ; Chemisorption ; Desorption ; Glass ; Gravimetric analysis ; Hardness ; Mechanical properties ; Nanoindentation ; Quartz ; Substrates ; X ray diffraction ; X ray diffraction analysis ; X ray photoelectron spectroscopy ; Annealing ; Biomaterial ; Nanomaterial ; Titanium ; Titanium dioxide ; Artificial membrane ; Chemistry ; Surface property ; Ultrastructure ; Biocompatible Materials ; Materials Testing ; Membranes, Artificial ; Nanostructures ; Particle Size ; Surface Properties ; Tensile Strength
  8. Source: ACS Applied Materials and Interfaces ; Volume 2, Issue 9 , 2010 , Pages 2629-2636 ; 19448244 (ISSN)
  9. URL: http://pubs.acs.org/doi/abs/10.1021/am100455q