Collaborative Research: Extreme Enhancement of the Electromechanical Properties of Soft Nano-Particulate Composites via Interphases

这个合作研究项目涉及的理论和实验相结合的调查和他们的作用，在有限变形和有限电场下的介电弹性体纳米颗粒复合材料的宏观机电响应的增强。虽然这种新兴类型的纳米复合材料的显着的机电性能已被链接到interphasial现象周围的纳米粒子，精确的（定量）的性质，界面的存在如何改善宏观性能仍然在很大程度上没有得到解决。这种基本的理解对于推进这类有前途的材料作为下一代致动器和传感器的技术开发至关重要。开发的一般数学框架也将直接适用于广泛的其他颗粒增强复合材料。该项目将培训两名研究生从事学术或工业职业，并将把研究成果纳入伊利诺伊大学厄巴纳-香槟分校和宾夕法尼亚州立大学的本科生和研究生课程。PI还将开发可视化实验，说明介电弹性体纳米颗粒复合材料作为下一代软致动器的潜力，以融入高中的推广活动。该项目的主要目标是：（i）获得代表性类别的介电弹性体纳米颗粒复合材料中的界面中和界面周围的几何形状、机电性质和空间电荷分布的实验测量，（ii）推导并数值实现一个高度易处理的均匀化框架，以描述包含空间电荷的界面对纳米颗粒复合材料宏观机电行为的影响，以及（iii）部署这个框架来探索具有最佳增强电致伸缩能力的纳米颗粒复合材料的设计。目标（i）需要实验覆盖纳米到宏观的长度尺度，而目标（ii）需要一个广义的，但易于处理的宏变量的定义，能够占相间现象及其稳定和收敛的数值实现在非凸设置的有限变形和有限的电场。

This collaborative research project concerns a combined theoretical and experimental investigation of interphases and their role in the enhancement of the macroscopic electromechanical response of dielectric elastomer nanoparticulate composites under finite deformations and finite electric fields. While the remarkable electromechanical properties of this emerging type of nanocomposites have been linked to interphasial phenomena around the nanoparticles, the precise (quantitative) nature of how the presence of interphases improves the macroscopic properties remains largely unresolved. Such a fundamental understanding is of utmost importance for advancing the technological exploitation of this promising class of materials as the next generation of actuators and sensors. The general mathematical framework developed will also be directly applicable to a wide range of other particulate reinforced composites. The project will train two graduate students for careers in academia or industry and will integrate research results in the undergraduate and graduate curricula at the University of Illinois Urbana-Champaign and the Pennsylvania State University. The PIs will also develop visual experiments illustrating the potential of dielectric elastomer nanoparticulate composites as the next generation of soft actuators to integrate into outreach to high schools.The main objectives of the project are to: (i) obtain experimental measurements of the geometry, electromechanical properties, and space charge distribution in and around interphases in representative classes of dielectric elastomer nanoparticulate composites, (ii) derive and numerically implement a highly tractable homogenization framework to describe the effect of interphases containing space charges on the macroscopic electromechanical behavior of nanoparticulate composites, and (iii) deploy this framework to explore the design of nanoparticulate composites with optimally enhanced electrostriction capabilities. Objective (i) entails experiments covering nanoscopic to macroscopic length scales, while objective (ii) entails a generalized yet tractable definition of macrovariables capable to account for interphasial phenomena and its stable and convergent numerical implementation in the non-convex setting of finite deformations and finite electric fields.