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

生物电子学和软机器人技术需要能够在拉伸或压缩时发挥作用的电子材料。软聚合物与金属的复合材料在室温或接近室温下是液态的，最近得到了科学界对此类应用的广泛关注。作为可伸缩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。先前的研究主要集中在扩大这些复合材料的应用前景，但对其电老化和失效机制的了解相对较少。缺乏相关知识可能导致过早失效，并可能使未来利用液态金属聚合物复合材料的技术面临风险。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气性能和击穿的关键特性。通过该项目建立的理解，未来的软电子技术可以开发具有特定应用性能和长期耐用性的技术。这个项目的新发现将被用来促进代表性不足的少数民族学生对STEM的兴趣。在与女童子军现有关系的基础上，利用世界一流的高压实验室，将为年轻女性和K-12学生设计一系列聚合物、电容器和高压相关的实验。此外，将在阿拉巴马州和密西西比州的社区大学开设有关高压工程和电介质的短期课程，其中包括可变形电介质的用例，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、刺激竞争研究的既定计划（EPSCoR）和DMR的金属和金属纳米结构（MMN）计划共同资助。液态金属聚合物复合材料（LMPCs）具有高介电常数和低模量的优异性能。虽然之前的研究表明，复合材料配方可以调整，以满足软电容器和拉伸或压力传感器的特定需求，但很少有工作关注使用LMPCs作为电介质的长期影响。具体来说，LMPCs的介电老化和失效机制因应用特定的电应力而异，目前尚不清楚。该项目的目标是采用综合实验和建模方法，对控制LMPCs介电性能和老化机制的关键参数进行第一性原理理解。研究小组将研究液滴形状、尺寸、载荷、组成、机械载荷和电压应力类型对LMPCs介电常数、耗散系数、局部放电起始电压和介电强度的影响。将使用有限元分析仿真环境来模拟介电常数和介电强度变化的趋势。该项目的成果将使未来的可变形技术能够利用lmpc，不仅可以根据特定应用定制配方，还可以最大限度地提高设备寿命和介电完整性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.