Low-temperature dielectric properties of Langmuir–Blodgett ferroelectric polymer films
Low-temperature dielectric properties of Langmuir–Blodgett ferroelectric polymer films
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DOI：
10.1063/1.2838212
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发表时间：
2008-02
影响因子：
3.2
通讯作者：
X. Meng;H. Kliem;Tong Lin;J. Chu
中科院分区：
文献类型：
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作者：
X. Meng;H. Kliem;Tong Lin;J. Chu
研究了Langmuir-Blodgett技术制备的偏氟乙烯和三氟乙烯共聚物薄膜在300 ~ 150k温度范围内的介电性能。在~ 240 K以下，观察到介电损耗峰随着频率的增加而增加。研究了材料在不同温度下的非线性介电磁化率和铁电性能。结果表明，在~ 230 K时，非线性介电磁化率发生了显著的变化。结果表明，聚合物薄膜中存在β弛豫，这与非晶相分子运动的冻结有关。在~ 230 K时，电学性质的异常是由于分子链运动的冻结。
Dielectric properties of the copolymer of vinylidene fluoride and trifluoroethylene films derived from the Langmuir–Blodgett technology have been investigated over the temperature range from 300 to 150 K at various frequencies. Below ∼240 K, peaks in the dielectric loss were observed to increase with increasing frequency. Nonlinear dielectric susceptibility and ferroelectric properties have been studied at different temperatures. The results show that the nonlinear dielectric susceptibility undergoes a remarkable change at ∼230 K. The results suggest a β relaxation, which is related to the freezing of the molecular motions in the amorphous phase in the polymer films. The anomaly in the electrical properties at ∼230 K is due to the freezing of the molecular chains motions.