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Journal of Nanotechnology
Volume 2011, Article ID 380979, 7 pages
http://dx.doi.org/10.1155/2011/380979
Research Article

Antibacterial Activity of Hydrophobic Composite Materials Containing a Visible-Light-Sensitive Photocatalyst

1Collaborative Research Center, Daido University, 10-3 Takiharu-cho, Minami-ku, Nagoya 457-8530, Japan
2Kanagawa Academy of Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa 213-0012, Japan
3Department of Urology and Molecular Science, Graduate School of Medicine, Yokohama City University 3-9 Fukuura, Kanazawa-ku, Yokohama 236-004, Japan
4Division of Photocatalyst for Energy and Environment, Research Institute for Science and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan
5Department of Information Design, Daido University, 10-3 Takiharu-cho, Minami-ku, Nagoya 457-8530, Japan

Received 15 March 2011; Revised 25 August 2011; Accepted 7 September 2011

Academic Editor: J. Anthony Byrne

Copyright © 2011 Kentaro Yamauchi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The conventional superhydrophobic surface offered by PTFE provides no sterilization performance and is not sufficiently repellent against organic liquids. These limit PTFE's application in the field of disinfection and result a lack of durability. N-doped TiO2 photocatalyst added PTFE composite material was developed to remedy these shortcomings. This paper reports the surface characteristics, and the bactericidal and self-cleaning performance of the newly-developed composite material. The material exhibited a contact angle exceeding 150 degrees consistent with its hydrophobicity despite the inclusion of the hydrophilic N-doped TiO2. The surface free energy obtained for this composite was 5.8 mN/m. Even when exposed to a weak fluorescent light intensity (100 lx) for 24 hours, the viable cells of gram-negative E. coli on the 12% N-doped TiO2-PTFE film were reduced 5 logs. The higher bactericidal activity was also confirmed on the gram-positive MRSA. Compared with the N-doped TiO2 coating only, the inactivation rate of the composite material was significantly enhanced. Utilizing the N-doped TiO2 with the PTFE composite coating could successfully remove, by UV illumination, oleic acid adsorbed on its surface. These results demonstrate the potential applicability of the novel N-doped TiO2 photocatalyst hydrophobic composite material for both indoor antibacterial action and outdoor contamination prevention.