TITLE:
The Synergistic Antibacterial Performance of a Cu/WO3-Added PTFE Particulate Superhydrophobic Composite Material
AUTHORS:
Kentaro Yamauchi, Tsuyoshi Ochiai, Goro Yamauchi
KEYWORDS:
Cu/WO3, Photocatalyst, PTFE, Hydrophobicity, Particulate, Composite, Synergistic Antibacterial Performance, Escherichia coli, MRSA
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.6 No.1,
January
6,
2015
ABSTRACT: The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus
and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene)
particulate composite was reported in the previous paper. The origin of the synergistic
antibacterial performance investigated by evaluating the photocatalytic decomposition of the
Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of
Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic
composite does not deteriorate the superhydrophobic property of the composite. Furthermore the
existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the
antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this
study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated
by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible
light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80
wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12
wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of
visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive
photocatalytic property appears only when PTFE concentration is larger than the critical
point over which superhydrophobic property appears in accordance with the particulate composite
model derived by the one of the authors. The hydrophobic surface leads to the low surface free
energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the
hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed
by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.