This document discusses using extrusion-calendering and thermo-compression processes to control the crystallization of PVDF/PMMA blends into the polar beta phase for applications in sensors, actuators, and energy harvesters. Extrusion-calendering at high cooling rates was found to produce the beta phase with only 5% PMMA content, while thermo-compression at lower cooling rates required 25-30% PMMA. The crystallization behavior was analyzed using flash DSC, FTIR, and WAXS techniques. Tuning the dielectric properties from ferroelectric to relaxor/antiferroelectric behavior may be possible with these processing methods.

1.  PVDF: Semi-crystalline ferroelectric &
piezoelectric polymer
 Numerous smart applications (sensors, actuators,
energy harvester, etc.)
 Poor control over its crystallization into the polar b-
phase by melt processes
Partners
Authors
Alexandre DE NEEF1,2
Cédric SAMUEL2
Jean-Marie RAQUEZ1
Jérémie SOULESTIN2
Philippe DUBOIS1
1University of Mons, SMPC
Laboratory (Belgium)
2IMT Lille Douai, Department
TPCIM (France)
PVDF/PMMA 90:10
 Crystallization behavior up to 4000°C/s
 Detection of an a-to-b crystal transition at high cooling rates
 In agreement with experimental observations on melt-processed PVDF/PMMA blends
EXTRUSION-CALENDERING (high cooling rate)
 β-phase appears from 5% PMMA
 Significant impact of film thickness
THERMO-COMPRESSION (low cooling rate)
 β-phase appears between 25 – 30 % PMMA
DE NEEF Alexandre
alexandre.deneef@umons.ac.be
or
alexandre.de-neef@imt-lille-douai.fr
Neat PVDF
Polar β
phase
Non-polar
a phase
0%
10%
20%
30%
0%
5%
10%
20%
30%
ATR-FTIR Analysis Wt-%
PMMA
Wt-%
PMMA
0%
20%
25%
30%
40%
α
β
0%
5%
10%
20%
30%
α + b
β
Wt-%
PMMA
Wt-%
PMMA
α
WAXS Analysis
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 Extrusion-calendering as a promising processing technique for thin ferroelectric PVDF/PMMA films
 Direct production of polar b-crystals promoted by high cooling rates with an optimum PMMA content of
5 wt-%
 Possible tuning of dielectric behavior from ferroelectric to relaxor/antiferrolectric like behavior
 Perspectives: crystal size measurements, piezoelectric properties and energy harvesting experiments
Melt-State Processing of PVDF/PMMA Blends
(Extrusion-Calendering & Thermocompression)
Process-Crystallization Relationships (Flash
DSC, FTIR & WAXS)
Crystallization-Ferroelectricity Relationships
(Polarization & Piezoelectricity)
 A Miscible PVDF/PMMA Blends Approach
Collaborations
This work has been supported by
the Université de Mons (UMons,
LMPC) and the Ecole des Mines
de Douai (EM Douai, TPCIM).
LPCM thanks the Belgian Federal
Government Office of Science
Policy (SSTC – PAI 6/27) for
general support and is much
indebted to both “Région
Wallonne”, the European
Commission “FSE and FEDER”
and INTERREG-FWVL BioHarv
for financial supports.
Acknowledgments
Contact
Analysis by F(DSC):