Influence of In Situ Oxide Dissolution on the Bottom Morphologies of Detached TiO₂ Nanotube Films

Figure 4

Cross-sectional SEM of the dissolved interface between the tube bottom and the newly formed tubes. The bottom morphology of the upside layer changed from (a) closed to (b) partially open and finally to (c) fully open bottom ends. This corresponds to the third-step anodization time of (a) 15 min, (b) 30 min, and (c) 60 min.

(a)

(b)

(c)