Intrinsic Tuning of Poly(styrene-butadiene-styrene)-Based Self-Healing Dielectric Elastomer Actuators with Enhanced Electromechanical Properties
Intrinsic Tuning of Poly(styrene-butadiene-styrene)-Based Self-Healing Dielectric Elastomer Actuators with Enhanced Electromechanical Properties
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DOI：
10.1021/acsami.8b13785
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发表时间：
2018-11-07
影响因子：
9.5
通讯作者：
Wan, Chaoying
中科院分区：
文献类型：
--
作者：
Ellingford, Christopher;Zhang, Runan;Wan, Chaoying
通过与极性有机基团的化学接枝，对热塑性苯乙烯-丁二烯-苯乙烯（SBS）介电弹性体的机电性能进行了本质调谐。巯基乙酸甲酯（MG）与丁二烯嵌段在25℃的紫外条件下进行一步“点击”反应，在20 min内接枝率达到98.5 mol %（相对于存在的丁二烯），在10(3)Hz下相对介电常数提高到11.4，具有低tan δ。mg接枝SBS介电弹性体致动器的致动应变比SBS致动器大10倍，致动力比SBS致动器大4倍。mg -接枝的SBS显示出实现机械和电自愈的能力。3天后，电击穿强度恢复到原来的15%，断裂强度和断裂伸长率分别恢复了25%和21%。自愈行为的解释是引入了减少粘滞损失和应变松弛的极性MG基团。弱CH/pi键通过邻近MG酯和苯乙烯中心的部分带电（δ +）基团使聚合物链重新结合并恢复性能。因此，本征调谐可以提高介电弹性体的机电性能，并提供具有自修复力学和介电性能的新型致动器材料。
The electromechanical properties of a thermoplastic styrene-butadiene-styrene (SBS) dielectric elastomer was intrinsically tuned by chemical grafting with polar organic groups. Methyl thioglycolate (MG) reacted with the butadiene block via a one-step thiol-ene "click" reaction under UV at 25 degrees C. The MG grafting ratio reached 98.5 mol % (with respect to the butadiene alkenes present) within 20 min and increased the relative permittivity to 11.4 at 10(3) Hz, with a low tan delta. The actuation strain of the MG-grafted SBS dielectric elastomer actuator was 10 times larger than the SBS-based actuator, and the actuation force was 4 times greater than SBS. The MG-grafted SBS demonstrated an ability to achieve both mechanical and electrical self-healing. The electrical breakdown strength recovered to 15% of its original value, and the strength and elongation at break recovered by 25 and 21%, respectively, after 3 days. The self-healing behavior was explained by the introduction of olar MG groups that reduce viscous loss and strain relaxation. The weak CH/pi bonds through the partially charged (delta+) groups adjacent to the ester of MG and the delta- center of styrene enable polymer chains to reunite and recover properties. Intrinsic tuning can therefore enhance the electromechanical properties of dielectric elastomers and provides new actuator materials with self-healing mechanical and dielectric properties.