Poly(vinylidene fluoride-trifluoroethylene) based high performance electroactive polymers
Poly(vinylidene fluoride-trifluoroethylene) based high performance electroactive polymers
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DOI：
10.1109/tdei.2004.1285901
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发表时间：
2004-04-01
影响因子：
3.1
通讯作者：
Cheng, ZY
中科院分区：
文献类型：
--
作者：
Huang, C;Klein, R;Cheng, ZY
利用高能电子辐照处理对P（VDF-TrFE）进行缺陷改性或将VDF-TrFE与少量氯化单体共聚形成无序三元聚合物，我们证明了P（VDF-TrFE）基聚合物可以实现高机电响应。结果表明，在85 MV/m的电场下，拉伸和辐照68/32 mol%共聚物的横向应变为4.5%，横向机电耦合系数k（31）为0.65。此外，辐照共聚物还表现出较高的弹性能量密度，类似于1 J/cm(3)。对于PVDF基三元共聚物，如P（VDF-TrFE-CFE）三元共聚物（CFE：氯氟乙烯），可获得超过7%的电伸缩应变。为了阐明P（VDF-TrFE）基聚合物中缺陷改性引起的微观结构变化，对辐照共聚物进行了同步x射线测量，结果表明，辐照使极性相转变为非极性相。此外，x射线数据表明，外场可以以非极性相为代价诱导极性相，证实了场诱导的构象变化是观察到的高机电响应的原因。虽然改性PVDF基聚合物表现出最高的室温介电常数（60比10），但它仍然远远低于无机材料。实验结果表明，在共轭键中使用离域电子可以得到介电常数大于400的全有机复合材料。结果表明，在13 V/mum的低强度电场下，可以产生接近2%的应变，且弹性能密度高于0.1 J/cm(3)。应变与外加电场成正比，复合材料的弹性模量接近1 GPa。
Making use of defects modification to P(VDF-TrFE) via either high energy electron irradiation treatment or copolymerizing VDF-TrFE with a small amount of chlorinated monomer to form a random terpolymer, we demonstrate that high electromechanical responses can be realized in P(VDF-TrFE) based polymers. It will be shown that in the stretched and irradiated 68/32 mol% copolymer, a transverse strain of 4.5% and a transverse electromechanical coupling factor k(31) of 0.65 can be induced under a field of 85 MV/m. In addition, the irradiated copolymer also exhibits a high elastic energy density, similar to1 J/cm(3). For PVDF based terpolymers such as P(VDF-TrFE-CFE) terpolymer (CFE: chlorofluoroethylene), an electrostrictive strain of more than 7% can be obtained. To elucidate the microstructure changes due to the defects modification in P(VDF-TrFE) based polymers, synchrotron X-ray measurement was carried out on the irradiated copolymers and the results show that, the irradiation converts the polar-phase into a non-polar phase. In addition, X-ray date show that the polar-phase can be induced, at the expense of the non-polar phase, by external fields, confirming that the field induced conformation change is responsible for the observed high electromechanical responses. Although the modified PVDF based polymer exhibits the highest room temperature dielectric constant (60 versus below 10), it is still far below those in the inorganic materials. Experimental results show that by using delocalized electrons in conjugated bonds an all-organic composite with a dielectric constant more than 400 can be achieved. As a result, a strain of near 2% with an elastic energy density higher than 0.1 J/cm(3) can be induced under a low applied field of 13 V/mum. The strain is proportional to the applied field and the composite has an elastic modulus near 1 GPa.