Visible Light Irradiation-Mediated Drug Elution Activity of Nitrogen-Doped TiO₂ Nanotubes

Figure 4

(a) Cross-sectional views of water droplets on Ti, electropolished Ti, 100 nm TiO₂ nanotubes, and N-doped 100 nm TiO₂ nanotubes. (b) Graph showing water droplet contact angles at the surface of the nanotubes.

(a)

(b)