Wen Xin, Li Dongfan, Tan Kai, Deng Qian, Shen Shengping
State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Frontier Institute of Science and Technology, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710054, China.
Phys Rev Lett. 2019 Apr 12;122(14):148001. doi: 10.1103/PhysRevLett.122.148001.
Because of the flexoelectric effect, dielectric materials usually polarize in response to a strain gradient. Soft materials are good candidates for developing a large strain gradient because of their good deformability. However, they always suffer from lower flexoelectric coefficients compared to ceramics. In this work, a flexoelectriclike effect is introduced to enhance the effective flexoelectricity of a polydimethylsiloxane bar. The flexoelectriclike effect is realized by depositing a layer of net charges on the middle plane of the bar to form an electret. Experiments show that the enhancement of flexoelectricity depends on the density of inserted net charges. It is found that a charged layer with surface potential of -5723 V results in a 100 times increase of the material's flexoelectric coefficient. We also show that the enhancement is proportional to the thickness of electrets. This work provides a new way of enhancing flexoelectricity in soft materials and further prompts the application of soft materials in electromechanical transducers.
由于挠曲电效应，介电材料通常会响应应变梯度而极化。软材料因其良好的可变形性而成为产生大应变梯度的理想候选材料。然而，与陶瓷相比，它们的挠曲电系数总是较低。在这项工作中，引入了一种类挠曲电效应来增强聚二甲基硅氧烷棒的有效挠曲电性能。类挠曲电效应是通过在棒的中间平面沉积一层净电荷以形成驻极体来实现的。实验表明，挠曲电性能的增强取决于插入净电荷的密度。发现表面电势为 -5723 V 的带电层会使材料的挠曲电系数增加 100 倍。我们还表明，增强效果与驻极体的厚度成正比。这项工作提供了一种增强软材料挠曲电性能的新方法，并进一步推动了软材料在机电换能器中的应用。
