title: Integrated Nano- and Macroscale Investigation of Photoinduced Hydrophilicity in TiO2Thin Films.
abstract: The hydrophilicity of titanium dioxide has been investigated for films, deposited on glass by e-beam evaporation, being exposed to UV radiation and subjected to thermal annealing. The wettability alteration has been showed to depend upon both treatments, and insights into how to introduce more stable hydrophilicity into these films have been presented for the sake of boosting their commercial value. Observations from multiple length scales to assess the wetting behavior of as-deposited and high-temperature annealed samples were assessed through macroscopic measurements, i.e., water contact angle measurements, showing that the annealed crystalline samples, treated at 500 °C, are much more hydrophilic (SCA ≈ 20°) than as-deposited TiO2films (SCA ≈ 90°), and the nanoscopic experiments performed by amplitude modulation (AM) atomic force microscopy (AFM) indicated that this increased hydrophilicity is related to an enhanced adhesion force and surface energy, resulting in the partial crystallization of TiO2and the consequent formation of crystals on its surface rather than being related to morphologic differences. XRD and Raman measurements have highlighted that the crystallinity of the TiO2film is crucial in determining its hydrophilicity, in good agreement with the AFM study. The results also indicated that, after irradiation, the samples treated at 500 °C preserve their hydrophilicity for a significant time compared to previous studies.
authors: Department of Chemical and Environmental Engineering and ‡Laboratory for Energy and NanoScience (LENS), Masdar Institute of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE.
authors: Corrado
authors: C
authors: Garlisi
authors: Department of Chemical and Environmental Engineering and ‡Laboratory for Energy and NanoScience (LENS), Masdar Institute of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE.
authors: Gabriele
authors: G
authors: Scandura
authors: Department of Chemical and Environmental Engineering and ‡Laboratory for Energy and NanoScience (LENS), Masdar Institute of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE.
authors: Giovanni
authors: G
authors: Palmisano
authors: Department of Chemical and Environmental Engineering and ‡Laboratory for Energy and NanoScience (LENS), Masdar Institute of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE.
authors: Matteo
authors: M
authors: Chiesa
authors: Department of Chemical and Environmental Engineering and ‡Laboratory for Energy and NanoScience (LENS), Masdar Institute of Science and Technology , P.O. Box 54224, Abu Dhabi, UAE.
authors: Chia-Yun
authors: CY
authors: Lai