Photo-induced effects on self-organized TiO<sub>2</sub> nanotube arrays: the influence of surface morphology
Kontos, A G; Kontos, A I; Tsoukleris, D S; Likodimos, V; Kunze, J; Schmuki, P; Falaras, P; Kontos, A G; Institute of Physical Chemistry, NCSR ‘Demokritos’, 15310 Aghia Paraskevi Attikis, Athens, Greece; Kontos, A I; Institute of Physical Chemistry, NCSR ‘Demokritos’, 15310 Aghia Paraskevi Attikis, Athens, Greece; Tsoukleris, D S; Institute of Physical Chemistry, NCSR ‘Demokritos’, 15310 Aghia Paraskevi Attikis, Athens, Greece; Likodimos, V; Institute of Physical Chemistry, NCSR ‘Demokritos’, 15310 Aghia Paraskevi Attikis, Athens, Greece; Kunze, J; Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremberg, Martensstrasse 7 D-91058 Erlangen, Germany; Schmuki, P; Department of Materials Science and Engineering, WW4-LKO, University of Erlangen-Nuremberg, Martensstrasse 7 D-91058 Erlangen, Germany; Falaras, P; Institute of Physical Chemistry, NCSR ‘Demokritos’, 15310 Aghia Paraskevi Attikis, Athens, Greece
Журнал:
Nanotechnology
Дата:
2009-01-28
Аннотация:
Self-organized TiO<sub>2</sub> nanotubes with packed, vertically aligned morphology and different lateral characteristics were grown on Ti metal substrates by controlled electrochemical anodization in phosphate/HF and ethylene glycol/HF electrolytes. The wetting, photo-induced superhydrophilicity, and photocatalytic activity of the nanotubular materials were investigated under ultraviolet irradiation. The photoactivity of the TiO<sub>2</sub> nanotube arrays was analysed in terms of their morphological characteristics that were determined by means of scanning electron microscopy and atomic force microscopy in conjunction with geometrical modelling. The wetting and the UV-induced superhydrophilicity could be accordingly modelled by the Cassie–Baxter mode arising from the large scale roughness of the nanotubular arrays in combination with the Wenzel mode due to the small scale roughness induced by ridges at the outer tube surface. The photocatalytic activity of the TiO<sub>2</sub> nanotube arrays was further found to correlate quantitatively with the variation of the geometric roughness factor, verifying the strong impact of morphology on the photo-induced properties of the vertically oriented TiO<sub>2</sub> tubular architecture.
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