Figure 7.

Side‐view (a) and top‐view (b) SEM images of TiO₂ nanotube layers anodized in ethylene glycol and HF on non‐polished Ti plate. Side‐view (c) and top‐view (d) images of TiO₂ nanotube layers anodized in ethylene glycol and HF on polished Ti plate. SEM images of TiO₂ nanotube layers anodized in ethylene glycol and NH₄F without (e,f) and with (g,h) protective layer. Top view (i) and side view (j) of the sample anodized under conventional method; top view (k) and side view (l) of the sample anodized using the new method at 80 °C post‐baking temperature for 10 min. (a–d) Reproduced with permission.142 Copyright 2008, Elsevier. (e–h) Reproduced with permission.143 Copyright 2009, The Electrochemical Society. (i–l) Reproduced with permission.144