This document summarizes the development of a sensor based on polyvinylidene fluoride (PVDF). It discusses the objectives to develop the sensor and spin a PVDF filament with a diameter of 200μm. It describes the piezoelectric properties of PVDF and its molecular structure. Rheological tests were conducted to analyze viscosity and dynamic properties of PVDF at different temperatures. Spinning tests produced a filament diameter of 200μm but with variations. Physical tests on the filament showed good elongation and modulus. The development of the PVDF-based sensor was achieved.

1. Development of a PVDF based
sensor
Universite de Haute-Alsace
ENSITM
Nuno Pimenta

2. Objectives
 Development of a sensor
 Rheological characteristics
 Spinning a filament with a diameter
of 200µm
 Physical characteristics

3. Polyvinylidene fluoride (PVDF)
 Piezo, pyroelectric
properties.
 α, β, γ and δ.
 Applications such
as sensors of
pressure, heat, etc.

4. Polyvinylidene fluoride (PVDF)
 The vinylidene
fluoride monomer
 Properties:
– mechanical
– Thermal
– Electrical
– Chemical
resistance

5. Molecular structure
 α and β phases
 Linear polymer
− Two dipole
moments
− CF2
− CH2
 Electronegativety
difference in PVDF

6. α and β phases
 α phase
– Non polar
 β phase
– Highly polar
 Polarization
– Dipole moments
are randomly
oriented
– Application of an
electrical field

7. PVDF-TrFE copolymers
 Copolymers formed by vinylidene
fluoride and trifluoroethylene
– Higher temperatures
– New sensor shapes
– Higher level of piezoelectricity
– Does not require stretching
– Crystallize directly in a polar phase
(similiar to β phase of PVDF)

8. PVDF-TrFE polarization
 PVDF-TrFE require
only temperature
and an electrical
field

9. PVDF spinning
 Typical process:
− Extrusion of the
molten polymer
− Stretching
− Cooling
− Winding the Filament of
filament cupper
 Insertion of a
filament (cupper)

10. The different stages of the project
Rheological properties
Filament spinning
Physical properties
Insertion of cupper
filament

11. Results
 Rheological tests
– Viscosity curves
– Dynamic curves
– Viscosity in function of time
 Spinning tests
 Physical tests

12. Rheological tests
 Viscosity curves
10000
8000
6000 pvdf flow (230°c)
pvdf flow (240°C)
pvdf flow (250°C)
4000
pvdf flow (260°C)
pvdf flow (270°C)
2000 pvdf flow (295°C)
0
0,001 0,01 0,1 1 10 100 1000
-2000

13. Rheological tests
 Dynamic curves
3,50E+05
3,00E+05
2,50E+05
pvdf (250°C, 10%)
2,00E+05 storage
1,50E+05 pvdf(250°C, 10%)
loss
1,00E+05
5,00E+04
0,00E+00
0 200 400 600 800

14. Rheological tests
 Dynamic curves
3,00E+05
2,50E+05
2,00E+05
pvdf (260°C, 10%)
storage
1,50E+05
pvdf(260°C, 10%)
1,00E+05 loss
5,00E+04
0,00E+00
0 200 400 600 800

15. Rheological tests
 Dynamic curves
3,00E+05
2,50E+05
2,00E+05 pvdf (270°c, 10%)
storage
1,50E+05
pvdf (270°C, 10%)
1,00E+05 loss
5,00E+04
0,00E+00
0 200 400 600 800

16. Rheological tests
 Viscosity in
function of time
pvdf (200 pa)
4400
4300
4200
4100 pvdf (200 pa)
4000
3900
3800
0 5 10 15 20 25 30 35

17. Rheological tests
 Viscosity in function of time
pvdf (300 pa)
4800
4700
4600
4500
pvdf (250 pa)
4400
4300
4200
4100
0 10 20 30 40

18. Spinning tests
 Spinneret 1mm
250
200
250 500
diameter
150
250 300
240 300
100
270 500
50
0
13
15
17
19
21
23
25
27
29
11
1
3
5
7
9
samples

19. Spinning tests
 Spinneret 2mm, winding velocity
300rpm
300
250 1
2
200 3
diameter
4
150
5
100 6
7
50
8
0 9
10
13
15
17
19
21
27
29
11
23
25
1
3
5
7
9
samples

20. Spinning tests
 Spinneret 2mm, winding velocity
280rpm
300
250
200
diameter
150
100
50
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
samples

21. Physical tests
 Test 1
1200 4
3,5
1000
3
800
MODULE
2,5
FORCE
600 2
400 1,5
1
200
0,5
0 0
190 180 250 200 220 200 230 210 230 220 190 180 250 200 220 200 230 210 230 220
DIAMETER DIAMETER

22. Physical tests
 Test 2
1200 4,5
4
1000
3,5
800 3
MODULE
FORCE
2,5
600
2
400 1,5
1
200
0,5
0 0
200 190 200 210 220 180 230 180 200 220 200 190 200 210 220 180 230 180 200 220
DIAMETER DIAMETER

23. Physical tests
 Test 3
1200 4
1000 3,8
800 3,6
MODULE
FORCE
600 3,4
400 3,2
200 3
2,8
0
200 240 190 230 210 180 230 170 230 210 200 240 190 230 210 180 230 170 230 210
DIAMETER DIAMETER

24. Physical tests
 Test 4
1800 4,5
1600 4
1400 3,5
1200 3
MODULE
FORCE
1000 2,5
800 2
600 1,5
400 1
200 0,5
0 0
230 180 180 160 230 240 190 170 150 180 230 180 180 160 230 240 190 170 150 180
DIAMETER DIAMETER

25.  Physical properties for PVDF-TrFE
Properties PVDF-TrFE
Elongation (%) 29,95
Module (MPa) 917,47
Force (N) 3,26
Diameter (µm) 204

26. Conclusion
 Rheolgical characteristics
− Viscosity
 Spinning
− diameter of the filament was succesfully
obtained (200µm)
− big variations in diameter
→ modification of the cooling system
 Physical properties
− good elongation
 Development of a PVDF based sensor

27. References
 H. Kawai, The piezoelectricity of poly(vinylidene fluoride), J. Applied Phys. 8, pp 975, (1969).
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transverse mechanical deformation studied by SEM and dielectric relaxation,Ferroelectrics, 294, pp 73-83, 2003
 F.Bauer, H.Moulard, G.Samara, Advances in ferroelectric polymers for shock compression sensors, American Institute
of Physics, 1970
 Feng Xia, Hengfeng Li, Cheng Huang, M.Y.M.Huang, H. Xu, Francois Bauer, Z.Y.Cheng, Q.M.Zhang, Poly(vinylidene
fluoride-trifluoroethylene) based high performance electroactive polymers, Smart structures and materials 2003, 3-6
March, 2003
 W.Eisenmenger, H.Schmidt and B.Dehlen, Space charge and dipoles in Polyvinylidene, Brazilian Journal of Physics, vol.
29, 2, June 1999
 Larissa Pinheiro, Matheus Chaud, Pedro Nascente and Rinaldo Gregorio Jr, Morphology of PVDF, P(VDF-TrFE)
copolymers and PVDF/P(VDF-TrFE) blends, Acta Microscopica, vol. 12, 1, December, 2003
 F. Bauer, Properties of ferroelectric polymers under high prssure and shock loading, Institute Franco-Allemand de
Recherches
 Francois Bauer, PVDF shock sensors: Applications to polar materials and high explosives, IEEE transactions of
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 Lee Keun Yoon, Byung Kyu Kim, Compatibility of Poly(vinylidene fluoride) (PVDF)/ Polyamide 12(PA12) blends, Journal
of Applied Polymer Science, vol. 78, pp 1374-1380, 2000
 T.Koizumi, S. Usui, The dependence of shear and elongational viscosity on the molecular weight of Poly(vinylidene
fluoride), Journal of Applied Polymer Science, vol.71, 2381-2384, 1999
 Measurement specialties, Inc., Piezo film sensors technical manual