SNM: Modulation of Surface Topography for Scalable Contact Printing

有了这个奖项，罗切斯特大学的一个研究小组将开发一种可扩展的、通用的接触印刷工艺，广泛地造福于高分辨率显示器、光子学、传感器和设备的纳米制造。与传统的纳米制造工艺相比，纳米级印刷可能需要更少的能源，依赖于廉价的加工工具，产生更少的废物。一个多学科团队将把响应性形状记忆聚合物塑造成图案表面，并将界面附着力与表面微观结构、整体机械性能、接触负荷和温度历史联系起来。通过优化表面切换粘附的能力，研究还可以实现变革性技术，包括可流动切换的微流体、可切换的医用粘合剂、细胞培养和组织生长模板，以及简化复杂设备的拆卸，以回收材料进行回收或再利用。随着对形状记忆如何控制材料转移的理解的提高，研究人员将优化印刷参数，以获得大规模的无机和有机薄膜的稳健转移。为了完成这个项目，研究人员将与一家工业合作伙伴（eMagin）合作，通过制造工作的有机发光二极管微显示器来应用形状记忆接触印刷。本科生，包括来自代表性不足群体的学生，将参加旨在贯穿整个科学循环的密集模块化研究体验。通过将研究活动整合到大学课程中，包括团队授课的纳米制造课程，我们将探索一种创新的工程教育教学方法。项目活动将通过提供化学工程、机械工程、材料科学和化学等多学科的教育经验，提高学生进入劳动力市场的制造技能。该项目的技术目标是开发一种可扩展的纳米制造平台，用于具有成本效益的高分辨率有机和无机薄膜的增材印刷。目前基于弹性体的接触印刷主要依靠速率调制来控制邮票-基材界面的附着力和断裂。然而，速率调制必须针对每个油墨-衬底-戳印系统进行优化，并且将这种工艺适应于中微米和纳米尺度模式仍然具有挑战性。在这个项目中，研究人员将利用响应形状记忆聚合物网络，将其模塑成图案表面，以实现可切换的地形和粘附性，从而精确地提取和输送小部分材料，尺寸降至100纳米以下。邮票的机械性能和表面结构将被设计成经受热触发的地形变化，从而改变表面的粘合性能。研究目标是：(1)识别具有可切换机械性能和可调节表面能的形状记忆聚合物，用于接触式印刷印章；(2)使用具有明确定义的特征和特征阵列的图案形状记忆印章来执行，建模和优化地形切换，界面粘附和材料转移；(3)对经历过热机械应力的特征和表面进行物理，化学和机械表征；(4)演示薄膜的增材接触印刷成清洁，无缺陷和高分辨率有机发光二极管阵列。与其他图案方法不同，形状记忆接触印刷有效地利用了印刷材料，可扩展到大面积和柔性基材，并且不受光衍射或材料扩散的分辨率限制。一个核心前提是，随着时间的推移，制造途径必须是准确可靠的，没有难以解决的障碍来大面积采用该技术。研究人员将解决可能限制该方法可扩展性的问题，包括邮票循环和耐用性、清洁度和对齐。

With this award, a team of researchers at the University of Rochester will develop a scalable and versatile contact printing process to broadly benefit nanomanufacturing of high-resolution displays, photonics, sensors, and devices. Compared to conventional nanofabrication processes, nanoscale-printing potentially requires less energy, relies on inexpensive processing tools and generate less waste. A multidisciplinary team will mold responsive shape-memory polymers into patterned surfaces and relate interfacial adhesion to surface microstructure, bulk mechanical properties, and contact load and temperature history. By optimizing the surface's ability to switch adhesion, research could also enable transformative technologies including flow-switchable micro-fluidics, switchable medical adhesives, cell culture and tissue growth templates, and simplified demanufacture of intricate devices to recover materials for recycle or reuse. With an improved understanding of how shape-memory controls material transfer, investigators will optimize printing parameters to obtain robust transfer of inorganic and organic thin films on a large scale. To conclude the project, researchers will team with an industrial partner (eMagin) to apply shape-memory contact printing by manufacturing working organic light emitting diode microdisplays. Undergraduates, including students from underrepresented groups, will take part in intense, modular research experiences that are designed to cycle through the entire scientific loop. An innovative pedagogical approach to engineering education will be explored by integrating research activities into university courses including a team-taught course on nanomanufacturing. Project activities will enhance manufacturing skills of students entering the workforce by providing them multidisciplinary educational experiences in chemical engineering, mechanical engineering, materials science, and chemistry.This technical goal of this project is to develop a scalable nanomanufacturing platform for cost effective, high-resolution additive printing of patterned organic and inorganic thin films. Current elastomer-based contact printing primarily relies on rate modulation to control adhesion and fracture at the stamp-substrate interface. However, rate modulation must be optimized for each ink-substrate-stamp system, and it remains challenging to adapt such processes to meso- and nanoscale patterns. In this project, researchers will utilize responsive shape-memory polymer networks that are molded into patterned surfaces to enable switchable topography and adhesion for precise pick-up and delivery of small portions of materials down to sub-100 nm dimensions. The stamp's mechanical properties and surface structures will be designed to undergo heat-triggered topographical changes, thereby imparting a change to the surface's adhesive properties. Research aims are: (1) to identify shape-memory polymers with switchable mechanical properties and tunable surface energies for use as contact-printing stamps; (2) to use patterned shape-memory stamps with well-defined features and arrays of features to perform, model, and optimize topographical switching, interfacial adhesion and material transfer, (3) to conduct physical, chemical, and mechanical characterization of features and surfaces that have experienced thermomechanical stresses, and (4) to demonstrate additive contact printing of thin films into clean, defect-free and high resolution organic light emitting diode arrays. Unlike other patterning methods, shape-memory contact printing makes efficient use of printed material, is scalable to large-area and flexible substrates, and is not limited in resolution by light diffraction or material diffusion. A central premise is that the manufacturing pathway must be accurate and reliable over time, with no intractable barriers to large-area adoption of the technology. Researchers will address issues that could limit the method's scalability including stamp cycling and durability, cleanliness, and alignment.