Effect of temperature on the crystalline phase and dielectric and ferroelectric properties of poly(vinylidene fluoride) film
Effect of temperature on the crystalline phase and dielectric and ferroelectric properties of poly(vinylidene fluoride) film
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DOI：
10.1177/1045389x13510217
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发表时间：
2014-05
影响因子：
2.7
通讯作者：
Lu Yang;H. Ji;J. Qiu;K. Zhu;B. Shao
中科院分区：
文献类型：
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作者：
Lu Yang;H. Ji;J. Qiu;K. Zhu;B. Shao
聚偏二氟乙烯作为一种功能高分子材料，因其优异的电活性性能而受到广泛关注。聚偏二氟乙烯的电活性性能在很大程度上取决于其晶体结构，而晶体结构又取决于加工条件。在我们最近的研究中，采用溶液结晶法制备了聚偏氟乙烯薄膜，并研究了蒸发温度对聚偏氟乙烯晶相、结晶度和形貌的影响。结果表明，蒸发温度是研究聚偏二氟乙烯晶体结构的关键因素。低温有利于β相的形核；然而，它们对于晶体成核和晶体生长是不利的。研究还发现，聚偏二氟乙烯薄膜的介电和铁电性能与β相结晶度密切相关。此外，在低蒸发温度下形成的多孔结构会导致介电性能和击穿强度下降。在80℃下制备的薄膜具有最高的β相结晶度（49％），并呈现出最大的εr（12.5，103Hz）和Pr（7μC/cm2），表明制备具有优异电活性性能的聚偏二氟乙烯薄膜的最佳温度是80℃。
As a functional polymer material, poly(vinylidene fluoride) has attracted broad attention due to its outstanding electroactive properties. The electroactive properties of poly(vinylidene fluoride) depend greatly on its crystalline structure, which in turn depends on the processing conditions. In our recent study, poly(vinylidene fluoride) films were prepared by a solution crystallization method, and the effect of evaporation temperatures on the crystalline phase, crystallinity, and morphology of poly(vinylidene fluoride) was investigated. The results reveal that evaporation temperature is the key factor when studying crystalline structure of poly(vinylidene fluoride). Low temperatures can facilitate the nucleation of β-phase; however, they are disadvantageous for the crystal nucleation and crystal growth. It was also found that the dielectric and ferroelectric properties are closely related to the crystallinity of β-phase of poly(vinylidene fluoride) films. Moreover, the porous structure formed in low evaporation temperatures can lead to a decline in dielectric property and breakdown strength. The films fabricated at 80 °C owned the highest crystallinity of β-phase (49%) and presented the maximum εr (12.5, 103 Hz) and Pr (7 µC/cm2), suggesting that the optimum temperature to prepare poly(vinylidene fluoride) films with excellent electroactive properties is 80 °C.