Pergamon-Elsevier Science Ltd. Acta Medica Okayama 0008-6223 49 10 2011 Superhydrophilicity on nano-rough carbon surfaces achieved by hyperthermal oxygen-atom beam exposure 3388 3391 EN Hiroshi Kinoshita Takashi Nakayama Naohiro Matsumoto Nobuo Ohmae In order to investigate a method to increase hydrophilicity on nano-rough carbon surfaces, a nano-rough surface of C(60) 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 sp(2) bonded carbon atoms (basal plane) of these two carbon materials by the exposure of hyperthermal O-atom beam would contribute the superhydrophilicity. No potential conflict of interest relevant to this article was reported.