COLLABORATIVE RESEARCH: Identifying the Dielectric Properties of Liquid-Metal Polymer Composites to Ensure the Dielectric Integrity of Deformable Electronic Applications

非技术概述生物电子学和软机器人要求电子材料在拉伸或压缩时仍能发挥作用。软聚合物与室温或接近室温的液态金属的复合材料最近在这类应用方面得到了科学界的广泛关注。作为可伸缩的电子元件和生理传感器，它们表现出了令人印象深刻的性能。以前的研究主要集中在扩大这些复合材料的前景，但相对较少的工作是了解它们的电老化和失效机制。缺乏知识可能导致过早失败，并可能使使用液态金属聚合物复合材料的未来技术面临风险。本项目将实验分析和数值模拟相结合，以确定导致液态金属聚合物复合材料独特电学性能和击穿的关键特征。有了通过这个项目建立的理解，未来的软电子技术可以在考虑到特定应用的性能和长期耐用性的情况下开发。这个项目的新发现将被用来促进STEM中代表不足的少数族裔学生的互考。在与女童子军现有关系的基础上，利用世界级的高压实验室，将为年轻女性和K-12学生设计一系列与聚合物、电容器和高压相关的实验。此外，在阿拉巴马州和密西西比州，将在社区学院开设高压工程和电介质学的短期课程，并提供可变形电介质材的用例，以促进大学招生。该项目由材料研究部(DMR)的电子和光子材料(EPM)计划、既定的促进竞争研究计划(EPSCoR)和DMR的金属和金属纳米结构(MMN)计划共同资助。技术概述液态金属聚合物复合材料(LMPC)通过同时提供高介电常数和低模数而显示出令人印象深刻的性能。虽然以前的研究已经证明，这种复合材料配方可以进行调整，以满足软电容器和张力或压力传感器的特定需求，但很少有人关注使用LMPC作为介质的长期影响。具体地说，LMPC的介电老化和失效机制因特定应用的电应力而异，目前尚不清楚。本项目的目标是采用综合的实验和建模方法，对控制LMPC介电性能和老化机理的关键参数进行第一性原理的理解。该团队将研究液滴形状、大小、负载、成分、机械负载和电压应力类型对LMPC的介电常数、损耗因数、局部放电起始电压和介电强度的影响。有限元分析模拟环境将被用来模拟介电常数和介电强度的变化趋势。该项目的成果将使利用LMPC的未来可变形技术不仅可以针对特定应用定制配方，还可以最大限度地提高器件寿命和介质完整性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical SummaryBioelectronics and soft robotics require electronic materials that function while being stretched or compressed. Composites of soft polymers with metals that are liquid at, or near, room temperature, have recently gained extensive attention from the scientific community for such applications. They have shown impressive performance as stretchable electronic components and for physiological sensors. Prior research has focused on expanding the promise of these composite materials, but relatively little has been done to understand their electrical aging and failure mechanisms. The lack of knowledge could lead to premature failure and may put future technologies utilizing liquid metal polymer composites at risk. This project combines experimental analysis and numerical modeling to identify the key characteristics that lead to the unique electrical performance and breakdown of liquid metal polymer composites. With the understanding established through this project, future soft electronic technologies can be developed with application-specific performance and long-term durability in mind. The novel findings of this project will be utilized to promote underrepresented minority student intertest in STEM. Building on the existing relationship with the Girl Scouts and by taking advantage of the world-class high-voltage lab, a series of polymer, capacitor, and high voltage-related experiments will be designed for young women and K-12 students. Furthermore, short courses on high-voltage engineering and dielectrics with use cases on deformable dielectrics will be delivered at community colleges to promote university recruitment in Alabama and Mississippi. This project is jointly funded by the Electronic and Photonic Materials (EPM) program of the Division of Materials Research (DMR), the Established Program to Stimulate Competitive Research (EPSCoR), and the Metals and Metallic Nanostructures (MMN) program of DMR. Technical SummaryLiquid metal polymer composites (LMPCs) have shown impressive performance by simultaneously providing high dielectric permittivity and low modulus. While previous research has demonstrated that the composite formulation can be tuned to address the specific needs of soft capacitor and tensile or pressure sensors, little work has focused on the long-term effects of using LMPCs as dielectrics. Specifically, the dielectric aging and failure mechanisms of LMPCs that vary by application-specific electrical stresses are currently unknown. The goal of this project is taking an integrated experimental and modeling approach to develop a first principles understanding of the key parameters governing the dielectric performance and aging mechanism of LMPCs. The team will investigate the effects of droplet shape, size, loading, composition, mechanical loading, and voltage stress type on the permittivity, dissipation factor, partial discharge inception voltage, and dielectric strength of LMPCs. A finite element analysis simulation environment will be used to model trends in permittivity and variation of the dielectric strength. The outcomes of this project will enable future deformable technologies that take advantage of LMPCs to not only tailor formulations to a specific application, but also maximize device lifetime and dielectric integrity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.