Fundamentals of Self-Aligned Capillary-Assisted Processes for Flexible Electronics

柔性电子产品的目标是将电子功能与机械灵活性相结合，以实现柔性显示器、可穿戴电子产品和柔性照明产品等应用。高性能电子设备需要精细的尺寸和精确排列的多种电子材料层；因此，该领域的一个关键挑战是开发一种能够在柔性基板上经济地生产这些架构的制造平台。该奖项支持一种新的基于液体油墨的制造工艺的基础研究，该工艺被称为电子(或标尺)自对准毛细辅助光刻。Scale有可能成为印刷柔性电子产品领域的一项颠覆性技术，因为它消除了一个重要的技术障碍，即需要精确对准打印的功能油墨层，降低成本，并使基于柔性电子产品的新产品成为可能，这些新产品将改善我们的生活质量。这些基础研究将影响许多科学和工程领域，包括印刷电子学、电子墨水开发、流体力学和界面现象。这些努力还包括为留住工程新生而设计的研究经验，制造业教材的开发和对工业的推广。SCALE涉及在柔性基板上压印由储液器、毛细管和设备结构组成的多层次、凹陷的开放网络，通过喷墨打印将具有电子功能的墨水输送到储液器中，并利用毛细作用选择性和顺序地填充特征，以制造电子元件、设备和电路。Scale有许多优点：它是可添加的、自对准的、高度并行的、可滚动到滚动(R2R)处理的，并且在可制造性和基板面积方面是可扩展的。基于规模的导电网络、电容器、电阻器和薄膜晶体管的特征尺寸在~5微米和更小的范围内，但另一方面，用于墨水输送的目标储油池要大一个数量级，这使得R2R方法成为可能。本研究采用流体力学建模、基础加工实验(包括高速可视化)和电子墨水开发相结合的方法来揭示R2R规模的科学和工程。该团队将在涂布工艺和可视化实验室中使用独特的多功能R2R涂层和印刷设备，以及R2R纳米压印设备来演示全R2R方法。

The goal of flexible electronics is to combine electronic functionality with mechanical flexibility to enable applications such as flexible displays, wearable electronics and flexible lighting products. High performance electronic devices require fine dimensions and precisely aligned layers of multiple electronic materials; hence, a key challenge in the field is developing a manufacturing platform capable of economically producing these architectures on flexible substrates. This award supports fundamental research on a new, liquid ink-based manufacturing process known as Self-Aligned Capillarity-Assisted Lithography for Electronics (or SCALE). SCALE has the potential to be a disruptive technology in the field of printed flexible electronics, because it removes a significant technological barrier, the need to precisely align printed layers of functional ink, reduces cost, and makes possible flexible electronics-based new products that will improve our quality of life. The fundamental studies will impact many scientific and engineering fields, including printed electronics, electronic ink development, fluid mechanics and interfacial phenomena. The efforts also include research experiences designed to retain freshmen in engineering, development of manufacturing educational materials and outreach to industry.SCALE involves imprinting a multilevel, recessed open network of reservoirs, capillaries and device structures on a flexible substrate, delivering electronically functional inks into the reservoirs by inkjet printing and using capillarity to selectively and sequentially fill features to create electronic components, devices and circuits. SCALE has many advantages: it is additive, self-aligned, highly parallel, amenable to roll-to-roll (R2R) processing, and scalable in terms of manufacturability and substrate area. SCALE-based conductive networks, capacitors, resistors and thin film transistors have features sizes in range of ~5 µm and below, but the target reservoirs for ink delivery, on the other hand, are an order of magnitude larger, which enables the R2R approach. This research uses a combined approach of fluid mechanics modeling, fundamental processing experiments, including high speed visualization, and electronic ink development to uncover the science and engineering of R2R SCALE. The team will use a unique Multifunctional R2R Coating and Printing Apparatus in the Coating Process and Visualization Lab, as well as a R2R nanoimprinting apparatus to demonstrate an all R2R approach.