CAREER: Electro-Mechanical Behaviors of Soft Conductive Composites Embedded with Liquid Metal Fiber Networks

这项教师早期职业发展（Career）基金将支持液态金属纤维网络复合材料机电行为的基础研究。由于其独特的微结构结构，这种新型软导电复合材料具有超拉伸性、高导电性、轻量化和低成本。因此，这种液态金属纤维网络复合材料将极大地有利于美国的柔性电子工业，并将具有其他重要的技术应用，如软传感器和执行器、软机器人、能量采集器等。本研究将首先提供表征和更好地理解大变形下液态金属纤维网络复合材料的微观组织演变和机电行为。这些新知识对液态金属纤维网络复合材料的微观结构设计、材料加工和工程分析至关重要，有助于未来的工程应用。研究和教育的整合将重点放在学生培训和行业参与上，以培养更多从事液态金属材料研究和设计的工程师。教育和推广计划将为K-12和本科生提供互动和动手活动，让他们发明自己的软电子产品。其他重要的教育目标包括开发新的课程、举办在线网络研讨会和维护液态金属材料的网页。研究的具体目标是发现网络几何形状对液态金属纤维网络复合材料机电行为的影响。将采用实验-理论-计算相结合的方法来揭示极大变形下的网络几何演化，表征光纤和网络尺度上的机电行为，并建立考虑材料各向异性和非亲和性的多物理场本构建模框架。微观结构、纤维和结形态以及机械变形对液态金属纤维网络复合材料的几何演化和机电行为的影响将被阐明和建模。所研究的本构模型和计算细观力学模型将通过各种实验技术进行验证，包括微纳米计算机断层成像、原位网络几何跟踪和同步机电测试。具有不同微观结构结构的液态金属纤维网络复合材料将使用PI独特开发的技术制造和表征。所研究的理论模型、仿真工具和实验方法将适用于广泛的软导电复合材料。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。

This Faculty Early Career Development (CAREER) grant will support fundamental research on the electro-mechanical behaviors of liquid metal fiber network composites. This new paradigm of soft conductive composites is super-stretchable, highly conductive, lightweight, and low cost due to its unique microstructural architectures. Therefore, such liquid metal fiber network composites will greatly benefit the flexible electronics industry in the USA and will have other important technological applications such as soft sensors and actuators, soft robotics, energy harvesters, etc. This research will first provide characterization and better understanding of the microstructural evolution and electro-mechanical behaviors of liquid metal fiber network composites under large deformation. Such new knowledge is critical to the microstructural design, material processing, and engineering analysis of liquid metal fiber network composites for future engineering applications. The integration of research and education will focus on student training and industry engagement to educate more engineers doing research and design for liquid metal materials. The education and outreach program will offer interactive and hands-on activities for K-12 and undergraduate students to invent their own soft electronics. Other key education objectives involve developing a new curriculum, hosting online webinars, and maintaining a webpage for liquid metal materials. The specific goal of the research is to discover the influence of network geometry on electro-mechanical behaviors of liquid metal fiber network composites. An integrated experimental-theoretical-computational approach will be employed to uncover the network geometry evolution under extremely large deformation, characterize electro-mechanical behaviors across fiber and network scales, and establish a multiphysics constitutive modeling framework considering material anisotropy and non-affinity. The effects of microstructural architectures, fiber and junction morphologies, and mechanical deformation on the network geometry evolution and electro-mechanical behaviors of liquid metal fiber network composites will be elucidated and modeled. The researched constitutive models and computational micromechanics models will be verified by various experimental techniques involving micro- and nano-computed tomography imaging, in-situ network geometry tracking, and synchronized electro-mechanical testing. Liquid metal fiber network composites with different microstructural architectures will be fabricated and characterized using techniques uniquely developed by the PI. The researched theoretical models, simulation tools, and experimental methodology will be applicable to a broad class of soft conductive composites.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.