CAREER: Manufacturing of Solid Particle-Liquid Metal Mixtures for Soft Robotics and Stretchable Electronics

该学院早期职业发展（CAREER）资助建立了一种可扩展的制造方法，通过界面工程方法控制其反应性和润湿特性，将各种固体颗粒添加剂纳入室温液体金属中。这项工作提供了新的基础知识，使创建一个新的多相导电膏类与可定制的物理，流变和化学性质。增强的性能提高了使用液态金属浆料进行基于挤出的三维（3D）打印的适用性，并在软机器人和可拉伸电子产品中产生了新的应用，这有助于美国制造业的经济和社会进步。固体颗粒-液体金属混合物是用于各种应用（例如控制系统、软物质致动器和分布式传感器）的增材制造的合适材料。该研究由新的学习模块补充，这些模块旨在通过将创业素养与以增材制造，材料加工和数字建模为重点的研究活动相结合，积极吸引整个教育领域的学生。这些模块通过当地项目和移动的科学实验室提供给内布拉斯加州和其他地方的学校和教师，以加强种族，地理和社会经济多样化学生的课堂学习。本研究的目标是建立一个通用的战略，将固体颗粒添加剂到液体金属，以提高其物理和流变性能，而不损害其流体属性。典型地，固体颗粒添加剂是金属如镍、钨或铜，液体金属是镓或其化合物。镓基液态金属的高反应性和内聚能在固液界面处提出了挑战，这些挑战通过界面工程方法来克服，其中引入中间层以同时充当腐蚀屏障和润湿剂。固体颗粒-液体金属混合物通过在受控条件下经由机械剪切进行混合而产生。随后表征物理性质、流变行为和化学稳定性以建立工艺-性质-性能关系，从而了解颗粒组成、体积负载和尺寸如何影响颗粒-液体金属混合物的性质和性能。改进的性能、增强的化学稳定性和在三维中图案化结构的能力使颗粒-液体金属混合物能够采取一系列形式，从复合材料中的离散夹杂物到图案化的液体网络。这项研究使设计和制造的材料和结构量身定制的软结构，设备和系统的灵感来自生物学。该项目是由先进制造（AM）计划，建立计划，以刺激竞争力的研究（EPSCoR），和民用，机械与制造创新（CMMI）部门。该奖项反映了NSF的法定使命，并且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 establishes a scalable manufacturing approach for incorporating diverse solid particle additives into room temperature liquid metals by controlling their reactivity and wetting characteristics through an interfacial engineering approach. This work provides new fundamental knowledge that enables the creation of a novel class of multiphase conductive pastes with customizable physical, rheological, and chemical properties. The enhanced properties increase the suitability of using liquid metal pastes for extrusion-based three-dimensional (3D) printing and lead to new applications in soft robotics and stretchable electronics, which contribute to the economic and societal advancement of U.S. manufacturing. The solid particle-liquid metal mixtures are suitable materials for additive manufacturing of a variety of applications such as control systems, soft matter actuators, and distributed sensors. The research is complemented by new learning modules that seek to actively engage students across the educational spectrum by integrating entrepreneurial literacy with research-based activities focused on additive manufacturing, materials processing, and digital modeling. These modules are delivered through local programs and via a mobile science lab to schools and teachers across Nebraska and elsewhere to enhance classroom learning for ethnically, geographically, and socio-economically diverse students. The goal of this research is to establish a universal strategy for incorporating solid particle additives into liquid metals to enhance their physical and rheological properties without compromising their fluidic attributes. Typically, the solid particle additive is a metal such as nickel, tungsten, or copper and the liquid metal is gallium or its compounds. The high reactivity and cohesive energy of gallium-based liquid metals offer challenges at the solid-liquid interface, which are overcome through an interfacial engineering approach where an intermediate layer is introduced to concurrently act as a corrosion barrier and wetting agent. The solid particle-liquid metal mixtures are created by mixing via mechanical shear under controlled conditions. The physical properties, rheological behavior, and chemical stability are subsequently characterized to establish the process-property-performance relationships to understand how the particle composition, volume loading, and size affect the properties and performance of the particle-liquid metal mixtures. The improved properties, enhanced chemical stability, and ability to pattern structures in three-dimensions enable particle-liquid metal mixtures to take a range of forms, from discrete inclusions in composite materials to patterned liquid networks. This research enables the design and manufacturing of materials and structures tailored for soft structures, devices and systems inspired by biology.This project is jointly funded by the Advanced Manufacturing (AM) Program, the Established Program to Stimulate Competitive Research (EPSCoR), and the Civil, Mechanical and Manufacturing Innovation (CMMI) Division.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.