Biomedical Engineering Reference
In-Depth Information
change of the matrix due to adsorbed vapor and the accompanying
change of the percolation-type conductivity. This type of composite
material shows a drastic change in the electrical conductivity
around a critical composition described as
.
Usually, it depends on the shape of the conducting filler. Generally,
the composite with higher aspect ratio of the conducting filler shows
the lower threshold and the sharper change in the conductivity
around the threshold. Therefore, composite materials equipped
with conducting filler of higher aspect ratio, like CNTs, are expected
to show higher sensitivities at room temperature.
percolation threshold
. [176] prepared a SWCNT/polypyrrole (PPy)
nanocomposite by a simple and straightforward
An
et
al
chemical
polymerization of a pyrrole and SWCNTs mixture. The composite
was then spin coated onto prepatterned IDE for electrical resistance
measurements toward exposure of tested gases. Figure 9.18 shows
in situ
Figure 9.18
SEM image of (a) pure polypyrrole (PPy), (b) purified CNT
bundles (diameter of 20 nm), and (c) the SWCNT/PPy
nanocomposite. The inset shows the optical microscope
image of the sensor Au/Ti microelectrodes, prepared by
sputtering onto SiO
/Si substrate. This figure is reprinted
and adapted with permission from Wiley [176].
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