Superhydrophilicity on nano-rough carbon surfaces achieved by hyperthermal oxygen-atom beam exposure

In order to investigate a method to increase hydrophilicity on nano-rough carbon surfaces, a nano-rough surface of C₆₀ film and an atomically flat surface of highly oriented pyrolytic graphite (HOPG) were oxidized by hyperthermal oxygen-atom beam exposure and the hydrophilicities of the surfaces were investigated. Superhydrophilicity were achieved on these exposed carbon surfaces, which had low O/C ratio of approximately 28% and surface roughness (Ra) of approximately 3 nm. The direct oxidations on sp² bonded carbon atoms (basal plane) of these two carbon materials by the exposure of hyperthermal O-atom beam would contribute the superhydrophilicity.