外部应力对P(VDF-TrFE)聚合物电热效应的影响（英文）

Influence of External Stress on the Electrocaloric Effect of P(VDF-TrFE) Copolymers

一个唯象的朗道·德文希尔理论被用来研究外部应力对P(VDF-TrFE)聚合物电热效应的影响。P(VDF-TrFE)(55/45)体材料和P(VDF-TrFE)(70/30)薄膜材料的电热效应极大地依赖于外部应力。外部应力和失配应变并不改变电热系数的最大值,但会减小电热系数最大值所对应的温度。对于P(VDF-TrFE)(55/45)体材料,张应力减小绝热温度改变值,并且最大的室温绝热温度改变发生在应力为180兆帕时。对于P(VDF-TrFE)(70/30)薄膜,张应力或压失配应变减小其绝热温度改变。而且,张应力和压应变同时作用可以导致大的室温绝热温度改变,这能为实际的制冷应用提供潜在的应用前景。

A phenomenological Landau-Devonshire theory is used to investigate the effect of external stress on the electrocaloric effect of P（VDF-TrFE） copolymers. The electrocaloric effects of P（VDF-TrFE） （55/45） bulk and P （VDF-TrFE） （70/30） thin films greatly depend on the external stress. The external stress or misfit strain does not change the maximum of the electrocaloric coefficient, but decreases the working temperature where the electroca- loric coefficient is maximized. For P （VDF-TrFE） （55/45） bulk, the tensile stress reduces the adiabatic temperature change and the giant room temperature adiabatic temperature change can be achieved at σ3 = 180 MPa. For P（VDF-TrFE） （70/30） thin films, the tensile stress or compressive misfit strain decreases the adiabatic tem- perature change. Moreover, the tensile stress together with the compressive misfit strain can result in the giant room temperature adiabatic temperature change which can not be achieved only by the misfit strain. It may provide the potential applications in refrigeration devices.