Biomedical Engineering Reference
In-Depth Information
frequency change versus mass change regulated by the well-known
Sauerbrey equation. Figure 9.40 shows the scheme of a QCM 10 MHz
sensor coated by a SWCNT LB layer onto double side.
Figure 9.40
(
) Schematic view of a QCM sensor with double side
coated by a SWCNT LB layer. (
Top-left
) Time response of a
QCM 10 MHz sensor, coated by a four-monolayer SWCNT LB
film, exposed at room temperature towards four different
concentrations of toluene. (
Top-left
) Comparison of QCM
responses of the sensors, coated by a four-monolayer SWCNT
LB film, exposed at room temperature toward toluene and
xylene. (
Down-right
) Comparison between toluene and xylene
sensitivities of the QCM sensors coated by a layer with
a different number of SWCNT monolayers. This figure is
adapted as referenced by Consales
Down-left
et. al
. [294].
. [294] demonstrated an SWCNT LB film as sensitive
coating for VOCs detection and applied to QCM and silica optical
fiber as well. In particular, a QCM 10 MHz quartz was used with a
double-side active layer. The response of the QCM sensor, coated by a
four-monolayer layer of SWCNTs, toward four gas concentrations of
toluene of 93, 73, 64, and 54 ppm, at room temperature, are shown in
Fig. 9.40. The frequency downshifts upon a given gas concentration
with a change proportional to the gas concentration under test, and
the signal is recovered upon dry air used as carrier and recovery gas.
Additionally, the QCM sensor has been exposed to another aromatic
compound such as m-xylene. The comparison, reported in the
Fig. 9.40, of the calibration curves for both volatile organic compounds
is shown for the entire range of tested gas concentrations. It can be
Consales
et al
