Creep and cycle life in polypyrrole actuators
Creep and cycle life in polypyrrole actuators
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DOI：
10.1016/j.sna.2006.03.016
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发表时间：
2007-01-08
影响因子：
4.6
通讯作者：
Hunter, Ian W.
中科院分区：
文献类型：
--
作者：
Madden, John D.;Rinderknecht, Derek;Hunter, Ian W.
导电聚合物致动器由于其低电压操作和相对较高的应变和力而引起人们的兴趣。然而，关于适当的操作载荷、蠕变程度和循环寿命的信息是不完整的。我们报告了在碳酸丙烯酯中工作的聚吡咯致动器的循环寿命和蠕变响应。在20 Mpa的压力下，100min后，聚吡咯薄膜的被动伸长率为2%，其中弹性伸长率约为1%。给出了高达60 Mpa应力下的蠕变试验结果，在很高的载荷下表现出非线性和历史相关的响应。蠕变的大小表明，在需要在不同载荷下进行位置控制的情况下，并且在长于数十分钟的时间内，聚合物最好在20兆帕的载荷下运行。在10 Mpa的平均载荷下，聚吡咯薄膜以8 Mpa的峰峰值被动循环100万次，没有表现出明显的疲劳现象，表明载荷不会限制循环寿命。通过施加方波电势循环的薄膜确实显示出有效应变的下降。在7000次循环后，应变幅值从2%下降到1%，并且在驱动过程中观察到蠕变速率的增加。当电势范围减小时，初始应变幅度为1.5%，32,000次循环后应变降至1%。应变幅度的减小与转移电荷的减少相关，这表明聚合物的降解是应变幅度损失的原因。(C)2006爱思唯尔B.V.保留所有权利。
Conducting polymer actuators are of interest due to their low voltage operation, and their relatively high strains and forces. However, information is incomplete regarding the appropriate operating loads, the extent of creep and cycle life. We report cycle life and creep response in polypyrrole actuators operated in propylene carbonate. Polypyrrole films are found to extend passively by 2% after 100 min at 20 MPa, including about 1% elastic elongation. Results of creep tests at stresses of up to 60 MPa are presented, showing a non-linear and history dependent response at very high loads. The magnitude of the creep suggests that in situations where position control is desired under varying loads and at times of longer than tens of minutes that the polymer is best operated at loads of < 20 MPa. Polypyrrole films passively cycled at a peak-to-peak amplitude of 8 MPa under an average load of 10 MPa for one million cycles show no apparent fatigue, suggesting that loading is not limiting cycle life. Films cycled by applying square wave potentials do show a drop in active strain. The strain amplitude decreases from 2% to 1% after 7000 cycles and an increased rate of creep is also observed during actuation. When the potential range is reduced such that the initial strain amplitude is 1.5% the strain drops to 1% after 32,000 cycles. The reduction in strain amplitude correlates with a decrease in charge transferred, suggesting degradation of the polymer is the cause of the loss in strain amplitude. (c) 2006 Elsevier B.V. All rights reserved.