Biomedical Engineering Reference
In-Depth Information
Top electrode
Active area
PVDF nanofiber webs
Diameter: 1 cm
Bottom electrode
Figure 8.17
(a) Schematic of PVDF nanofiber-based sensor and (b) piezoelectric signal-
generating device set-up by imparting the repeated sinusoidal external pressure to the
sensor with the active area (diameter: 1.0 cm).
Dipole reversibility
Pressure imparted
Pressure imparted
Pressure released
Pressure released
0
1
2 3
Time (sec)
4
5
0
1
3
Time (sec)
2
4
5
(a)
One layer of nanofiber webs (t=70
μ
m)
Four layers of nanofiber webs
16 layers of nanofiber webs
Pressure imparted
2.0
8
4
0.4
0.2
1.5
1.0
0.5
0.0
0
0.0
−
4
−
0.5
−
0.2
−
1.0
−
8
Pressure released
−
0.4
−
1.5
0
2
4 6
Time (sec)
8
10
0
2
4 6
Time (sec)
8
10
0
2
4 6
Time (sec)
8
10
(b)
Figure 8.18
Effects of (a) polarity direction and (b) number of stacked layers with the
same polarity direction on the piezoelectric signal of PVDF nanofiber web sensor. The
thickness of each layer of PVDF nanofiber web is around 70
μ
m.
8.5.2
Touch Sensor Based on a PVDF Electrospun Web with CaCl
2
and CNTs [20]
Sun Yoon and Kap Jin Kim
A flexible touch sensor was produced based on a PVDF web with CaCl
2
and CNTs,
as described in Section 8.3.2. A schematic representation of the sample set-up
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