Flexible Nanogenerator and Nano-Pressure Sensor Based on Nanofiber Web of PVDF and its Copolymers - Soft Fibrillar Materials: Fabrication and Applications - page 254

Figure 8.25 Plotted line
of measured peak-to-
peak voltage of sensors:
(a) P(VDF-TrFE) (55/45),
(b) P(VDF-TrFE) (77/23),
and (c) PVDF.

5 a

b
c

4

3

2

1

0

0.01 0.02 0.03 0.04 0.05 0.06

F (N)

Table 8.4

Sensitivity of the sensors in the series of measurements.

Sample (mole ratio of VDF) Sensitivity (mV/N)

55 32.9

77 60.5

100 40.6

8.6
Conclusion

PVDF and its copolymer have been investigated and used widely in sensors,
actuators, and generators. However, the rigidity, fragility, and poor permeability
of polymer film limit its applications in some fields. A nanofibrous web of
piezoelectric polymer has more advantages in mechanical properties than a film.
There are many methods for preparing nanofibers, electrospinning being a simple
and efficient method. With the development of electrospinning technology, not
only can nanofibers be produced in large quantities, but complex structures can
also be prepared, such as composite and aligned fibers.
This chapter describes some of our work on electrospun fibrous web and flexible
devices based on a fibrous web of PVDF and its copolymer. Results show that
nanoscale fibers could be prepared by electrospinning, and high electric field
and high ratio stretch influence the crystal structure of PVDF and its copolymer.
Experiments on various electrospinning processes have shown that there is a
optimal electrospinning scheme for preparing the best fibers. Also, metal salts in
polymer fibers can improve the structure of the fibers, so that fibers with metal salts
perform better in practicalapplications. Furthermore, the copolymer P(VDF-TrFE)
has been shown to have some advantages over PVDF. There are more polar β-phase