Inkjet-Electrospray Hybrid Printing: Understanding the Processing-Structure Relationship

制造功能材料薄膜的能力满足了许多应用的重要技术需求，包括：柔性电子，生物传感，光学涂层，能量转换/收集和数据存储。作为占主导地位的薄膜制造技术之一，材料印刷支撑着数十亿美元的产业。然而，目前的印刷方法已经达到了一个基本的限制，抑制了薄膜加工的创新。这项研究的总体目标是提供急需的知识，以创建一种高分辨率，可扩展的技术，可以实现使用各种功能油墨的印刷图案的大规模生产。这项新技术将为制造商提供一种独特的工具，用于打印工业应用和消费产品的新型材料。这项研究的成功将为改变薄膜加工的范式奠定基础，并将对加速美国的制造业创新产生影响。此外，本科生和研究生融入这项研究将为行业提供他们所需的高素质和经验丰富的人才，以扩大薄膜增材制造的商业用途。该项目旨在将联合收割机喷墨技术和电喷雾打印结合起来，创造一种混合打印技术，提供光刻和传统打印的优点，即高特征分辨率，材料多功能性，材料保护和微观结构控制。使用电喷雾，干燥的胶体材料被递送到喷墨打印的牺牲细流的表面以形成胶体单层。随后在完全蒸发细流后将单层转移到基底上，以产生自组装的紧密堆积的纳米颗粒单层。通过在单个颗粒的长度尺度上控制存款结构，可以在单分子膜中出现独特的机械、电学和光学性质。本研究将结合计算模型和实验方法，以发现工艺参数，印刷动力学和最终存款结构之间的基本关系。先进的成像技术将被用来描述这个复杂系统和最终沉积物的时间演化。一种新的双向耦合拉格朗日粒子跟踪格子玻尔兹曼模型将开发提供基本的洞察纳米粒子的电喷雾，蒸发溪流的物理化学流体动力学，以及在界面和随后的沉积粒子的自组织。随着对这种混合打印过程的更深入了解，研究团队将设计和构建一个集成的混合打印头，其中包括喷墨喷嘴和电喷雾发射器，用于可扩展的处理。

The ability to create thin films of functional materials addresses vital technological needs for many applications, including: flexible electronics, bio-sensing, optical coatings, energy conversion/harvesting, and data storage. As one of the dominant thin film manufacturing techniques, printing of materials underpins multi-billion dollar industries. However, the current printing methods have reached a fundamental limit that has inhibited innovation in thin film processing. The overarching goal of this research is to provide the much-needed knowledge for creating a high-resolution, scalable technique that can achieve mass production of printed patterns using a variety of functional inks. The new technique will provide manufacturers with a unique tool to print novel materials for industrial applications and consumer products. The success of this research will lay the groundwork for changing the paradigm of thin film processing and will have an impact on accelerating manufacturing innovation in the United States. In addition, the integration of undergraduate and graduate students into this research will provide industry with the highly qualified and experienced personnel they need to expand the commercial use of thin film additive manufacturing.This project aims to combine inkjet technology and electrospray printing to create a hybrid printing technique that provides the advantages of photolithography and traditional printing, namely, high feature resolution, material versatility, material conservation, and control over microstructure. Using electrospray, dry colloidal material is delivered to the surface of inkjet-printed sacrificial rivulets to form colloidal monolayers. The monolayers are subsequently transferred to the substrate upon complete evaporation of the rivulets to create self-assembled, close-packed nanoparticle monolayers. Unique mechanical, electrical, and optical properties can emerge in the monolayers by controlling the deposit structure on the length scale of an individual particle. This research will integrate computational modeling and experimental approaches to discover the fundamental relationships among the process parameters, printing dynamics, and final deposit structure. Advanced imaging techniques will be used to characterize the time evolution of this complex system and the final deposits. A novel two-way coupled Lagrangian particle tracking-lattice Boltzmann model will be developed to provide fundamental insight into the electrospray of nanoparticles, the physico-chemical hydrodynamics of the evaporating rivulet, and the self-organization of particles at the interface and subsequent deposition. With a greater understanding of this hybrid printing process, the research team will design and build an integrated hybrid printhead that encompass an inkjet nozzle and electrospray emitter for scalable processing.