Photochemical modification of nanodiamond films with perfluorooctyl functionalities

Photolysis of perfluoroazooctane in the presence of nanodiamond films on Si substrate resulted in surface modification with perfluorooctyl functional groups, which was confirmed by means of FT-IR, XPS, Raman and TOF-SIMS measurements. The nanodiamond films modified with fluorine moieties show a reduction of the surface energy in comparison with pristine nanodiamond film. The contact angle of chemically modified nanodiamond film to water is 124°, comparable to that of polytetrafluoroethylene (103°). In the case of nanodiamond films deposited on glass substrate with a transparent property, this chemical modification would not influence the transparency of nanodiamond films, showing > 87% transmittance in the region of > 400 nm wavelength.