Collaborative Research: Designer Microstructures by Additive Manufacturing of Functional Emulsions

功能性乳液是一种新兴的材料体系结构，用于创建高功能弹性体复合材料，具有柔软和弹性可变形。然而，控制乳液中复合材料的局部组成和微观结构的技术是缺乏的，这些技术最终决定了固化弹性体复合材料的材料特性和性能。该奖项支持开发增材制造技术的基础研究，以控制乳液中的液体包裹体微观结构，从而在弹性体复合材料中实现前所未有的热、电和机械功能组合。通过开发材料和制造知识来编程包含微观结构，下一代功能材料的复合材料结构的新范式将在电子和机器人领域得到新的应用，这将有利于美国的经济和社会。通过团队成员制作的“研究背后”视频集合和9-12年级学生的制造研讨会，该项目为增材制造和软机器人等新兴领域的未来领导者提供灵感和培训。本项目建立了增材制造功能乳液的加工-结构-性能关系，该乳液可以固化成复杂几何形状的弹性体复合材料。这是通过创建模型乳胶油墨、加工方法和现场过程监测来实现的，以确定材料成分和印刷条件如何影响材料微观结构。这些基本的加工和材料的见解与新的理论模型相结合，用于乳化挤出，以预测整个制造部件的液相夹杂物的微观结构。液态金属和甘油液相包体表现出明显不同的基本性质，但它们都在软物质工程领域具有广泛的适用性。与具有固定形状和尺寸的刚性碳黑、铜或二氧化硅颗粒填料相比，通过直接墨水写入加工对液体包裹体形态的按需控制提供了一种新的高效制造弹性复合材料的方法。在制造过程中，积极定制局部材料成分和液体夹杂物微观结构，以控制弹性体复合材料的电学、热学和机械性能。通过将印刷油墨特性和过程控制与工具设计和建模相结合，这项工作为创建可扩展的加工乳剂制造策略提供了新的基础知识。这导致了具有可编程加工-结构-性能关系的新型模型材料系统，以确定多组分软物质的基于物理的特性。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。

Functional emulsions are an emerging material architecture for creating highly functional elastomer composites that are soft and elastically deformable. However, techniques to control local composition and microstructure of the composite material in emulsions, which ultimately govern material properties and performance of the cured elastomer composite, are lacking. This award supports fundamental research to develop an additive manufacturing technique to control liquid inclusion microstructure in emulsions to achieve unprecedented combinations of thermal, electrical, and mechanical functionalities in elastomer composites. By developing the material and manufacturing knowledge to program inclusion microstructure, new paradigms in composite architecture for next generation functional materials are enabled leading to new applications in electronics and robotics, which benefits the U.S. economy and society. Through a collection of ‘behind the research’ videos generated by team members and a manufacturing workshop for 9-12 grade students, the project provides inspiration and training for future leaders in the emerging fields of additive manufacturing and soft robotics.This project establishes the processing-structure-property relationships of additively manufactured functional emulsions that can be cured into an elastomer composite of complex geometry. This is achieved by creating model emulsion inks, processing methods, and in-situ process monitoring to determine how material composition and printing conditions influence material microstructure. These fundamental processing and material insights are combined with new theoretical models for emulsion extrusion to predict the microstructure of liquid phase inclusions throughout a manufactured part. Liquid metal and glycerol liquid phase inclusions are examined as they present distinctly different fundamental properties, but both offer broad applicability in the field of soft matter engineering. In contrast to rigid carbon black, copper, or silica particle fillers that have fixed shape and size, the on-demand control of liquid inclusion morphology via direct ink write processing provides a new and efficient method to manufacture elastomeric composites. During the manufacturing process, the local material composition and liquid inclusion microstructure are actively tailored to control the electrical, thermal, and mechanical properties of elastomeric composites. By combining printing ink properties and process control with tool design and modeling this work provides new fundamental knowledge to create scalable manufacturing strategies for processing emulsions. This leads to novel model material systems with programmable processing-structure-property relationships to determine physics-based properties of multi-component soft matter.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.