Large Electrocaloric Effect in Ferroelectric Polymers Near Room Temperature
Bret Neese,1,3
Baojin Chu,1,3
Sheng-Guo Lu,1
Yong Wang,2
E. Furman,1
Q. M. Zhang1,2*
Applying an electrical field to a polar polymer may induce a
large change in the dipolar ordering, and if the associated
entropy changes are large, they can be explored in cooling applications.
With the use of the Maxwell relation between the pyroelectric
coefficient and the electrocaloric effect (ECE), it was determined
that a large ECE can be realized in the ferroelectric poly(vinylidene
fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer at temperatures
above the ferroelectric-paraelectric transition (above 70°C),
where an isothermal entropy change of more than 55 joules per
kilogram per kelvin degree and adiabatic temperature change
of more than 12°C were observed. We further showed that
a similar level of ECE near room temperature can be achieved
by working with the relaxor ferroelectric polymer of P(VDF-TrFE-chlorofluoroethylene).
2 Electrical Engineering Department, The Pennsylvania State University, University Park, PA 16802, USA.
3 Materials Science and Engineering Department, The Pennsylvania State University, University Park, PA 16802, USA.
* To whom correspondence should be addressed. E-mail: qxz1{at}psu.edu
