Large electrocaloric effect in ferroelectric polymers near room temperature
Large electrocaloric effect in ferroelectric polymers near room temperature
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DOI：
10.1126/science.1159655
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发表时间：
2008-08-08
期刊：
影响因子：
56.9
通讯作者：
Zhang, Q. M.
中科院分区：
文献类型：
--
作者：
Neese, Bret;Chu, Baojin;Zhang, Q. M.
对极性聚合物施加电场可能会导致偶极有序性发生很大的变化，如果相关的熵变很大，则可以在冷却应用中进行探索。利用热释电系数与电热效应之间的Maxwell关系，确定了铁电聚偏氟乙烯-三氟乙烯[P(VDF-TrFE)]共聚物在铁电-顺电转变温度以上(70℃以上)可实现较大的电热效应，其等温熵变大于55焦耳/开文度，绝热温变大于12℃。我们进一步表明，通过与松弛铁电聚合物P(VDF-TrFE-氯氟乙烯)合作，可以获得接近室温的ECE值。
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 degrees C), where an isothermal entropy change of more than 55 joules per kilogram per kelvin degree and adiabatic temperature change of more than 12 degrees 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).