Electromechanical coupling behavior of nano-scale dielectric elastomer actuators

介电弹性体作动器因其重量轻、能量密度高、变形大等优点，成为最有前途的软材料机电转换技术之一，受到人们的广泛关注。它们具有广泛的潜在应用，如人工肌肉、自适应光学元件、软机器人、可编程触觉表面以及其他仿生应用。尽管这些器件已经获得了独特的机电耦合性能，但在理解这些软介电体的基本原理方面工作有限，特别是当介电弹性体的尺寸达到亚微米或纳米级时。为了促进这些介电弹性体作为致动器的全部潜在应用，需要为可靠的设计提供坚实的理论指导。 因此，本研究的目标是建立一个描述介电弹性体的机电耦合的稳健的理论框架，能够捕捉到大变形、非线性的材料行为和结构尺度特征。同时，对于更复杂、更一般结构的执行器，也将开发一种精确、稳定、高效的数值计算方法。这些解析和数值方法将被用来表征纳米介电弹性体作动器的机电耦合。本项目首次系统地研究了考虑纳米结构特征的介电弹性体的机电耦合行为。通过这项研究，我们期望通过探索现有介电弹性体致动器的微型化或开发介电纳米复合材料来定量地“设计介电”。所提出的理论和数值方法将为准确预测介电弹性体的机电耦合提供可靠的基础，从而为这些智能材料在传感技术中的应用提供更好的可控设计。

Dielectric elastomers actuators, emerged as one of the most promising technologies for soft material-based electromechanical transduction, have received much attention due to their light weight, high energy density and large deformation. They have extensive potential applications, such as artificial muscles, adaptive optical elements, soft robots, programmable haptic surfaces, and other biomimetic applications. Despite the fact that unique electromechanical coupling performance has been obtained for these devices, there is limited work on understanding the underlying fundamentals of these soft dielectrics, especially when the size of dielectric elastomers goes to submicro or nano level. To facilitate the full potential applications of these dielectric elastomers as actuators, it is desirable to develop a solid theoretical guidance for the reliable designs. It is, therefore, the objective of the proposed research to develop a robust theoretical framework describing the electromechanical coupling of dielectric elastomers, which is capable of capturing the large deformation, nonlinear material behavior and structure scale features. Meanwhile, an accurate, stable and efficient numerical method will also be developed for actuators with more complex and general configurations. These analytical and numerical methods will be used to characterize the electromechanical coupling of the nano-scale dielectric elastomer actuators. This project is the first to systematically study the electromechanical coupling behavior of dielectric elastomers considering nano-scale structure features. Through this study, we expect to quantitatively "design dielectricity" by exploring miniaturization of existing dielectric elastomer actuators or developing dielectric nanocomposites. The proposed theoretical and numerical approaches will provide a sound base for accurately predicting the electromechanical coupling of dielectric elastomers, thus lead to a better and controlled design for the applications of these smart materials in transduction technologies.