Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 4, pp. 615−618.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © I.A. Zhigaeva, M.F. Galikhanov, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 4, pp. 659−662.
Improving the Thermal Stability of the Electret Properties
of Corona Electrets Based on Fluoroplastic-32L
I. A. Zhigaeva and M. F. Galikhanov
Kazan National Research Technological University, Kazan, Tatarstan, Russia
Received July 12, 2012
Abstract—Corona electrets based on composites constituted by ﬂ uoroplastic-32L and powdered ferroelectric
ﬁ ller, barium titanate, were studied. It was found that introduction of a ferroelectric ﬁ ller into ﬂ uoroplastic-32L
improves the thermal stability of the electret properties by 30–40°.
The application range of polymeric electrets
extends from household appliances to special-purpose
technology. These are acoustic transducers, dosimeters,
gas ﬁ lters, electronic focusing systems, friction unit
elements, gaskets, means of corrosion protection,
voltmeters, and ﬁ lters [1–3]. Recently, new application
ﬁ elds of electrets in medicine and biotechnology have
opened up . Polymeric electrets frequently have poor
electret properties and short service life. At present,
much attention is given to studies aimed to improve the
electret properties of polymers by ﬁ lling, mixing, and
Electrets are frequently fabricated by polarization
of polymers in a corona discharge, whose advantages
are the technological simplicity and rather high process
rate. The electrization mechanism of this kind consists
in that charge carriers (electrons, ions) are injected into
a polymeric insulator and captured by energy traps, such
as impurities and structural anomalies [1, 2].
Fluorine-containing polymers are widely used to
fabricate electrets. To polymers of this kind belongs a
statistical copolymer of triﬂ uoroethylene and vinylidene
ﬂ uoride. However, electrets based on this polymer are
little described, despite that it could prove irreplaceable
in those cases when electret coatings combining a high
adhesion to a substrate with the optimal tribotechnical
and anticorrosive characteristics are needed.
At elevated temperatures, the electret properties of
ﬂ uoroplastic-32L are sharply deteriorated due to the
increased mobility of macromolecules in the polymer.
The stability of its electret properties can be improved
by ﬁ lling with solid particles, including those of
Ferroelectrics contain homogeneously polarized
regions, domains whose dipole moments are disordered
in the absence of an electric ﬁ eld. The resultant
domain structure commonly leads to a nearly full
compensation of the polarization. Application of a ﬁ eld
causes preferable orientation of the domains in a single
direction. The polarization of ferroelectrics decreases
with varying (commonly increasing) temperature and
disappears at the Curie point [9, 10]. It can be assumed
that introduction of a ferroelectric can markedly
improve the thermal stability of the electret properties
of polymeric ﬁ lms.
The goal of our study was to examine the stability
of the electret state in composites constituted by
ﬂ uoroplastic-32L and powdered ferroelectric at elevated
Fluoroplastic-32L was chosen as object of study.