US Patent 7687431 - TiO2 nanotube

http://www.freepatentsonline.com/7687431.html

Titanium dioxide has a variety of uses in pigments, photocatalysts, solar cells, and memristors. This patent from Nippon Oil teaches the fabrication of a nanotube form of TiO2 which may improve the responsiveness of the material to external stimulus. Claim 1 reads:

1. A nanotube-shaped titania with a diameter of 30 to 500 nm, a length of 0.9 to 100 microns and an aspect ratio of 30 or greater, obtained by anodizing a titanium metal or an alloy mainly containing titanium.