SNM: Modulation of Surface Topography for Scalable Contact Printing

有了这个奖项，罗切斯特大学的一组研究人员将开发一种可扩展和多功能的接触打印工艺，以广泛受益于高分辨率显示器、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，纳米打印可能需要更少的能源，依赖廉价的加工工具，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模塑成有图案的表面，并将界面粘附性与表面微结构、整体机械性能以及接触载荷和温度历史联系起来。通过优化表面的粘附性转换能力，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制造，以回收材料供回收或重复使用。随着对形状记忆如何控制材料转移的了解的加深，研究人员将优化打印参数，以获得大规模的无机和有机薄膜的稳健转移。为了完成该项目，研究人员将与一家工业合作伙伴(EMagin)合作，通过制造可工作的有机发光二极管微型显示器来应用形状记忆接触打印。本科生，包括来自代表性不足群体的学生，将参加紧张的、模块化的研究体验，这些体验旨在整个科学循环中循环。将探索工程学教育的创新教学方法，将研究活动纳入大学课程，包括一门关于纳米制造的团队授课课程。项目活动将通过为进入劳动力市场的学生提供化学工程、机械工程、材料科学和化学方面的多学科教育经验来提高他们的制造技能。该项目的技术目标是开发一个可扩展的纳米制造平台，用于低成本、高分辨率的图案化有机和无机薄膜的添加剂打印。目前基于弹性体的接触打印主要依靠速率调制来控制印章-基材界面的粘合和断裂。然而，速率调制必须针对每个油墨-基材-邮票系统进行优化，并且使这种过程适应中尺度和纳米尺度的图案仍然是具有挑战性的。在这个项目中，研究人员将利用具有响应性的形状记忆聚合物网络，将其模制成图案化的表面，以实现可切换的地形和附着力，从而精确地拾取和输送小部分材料，尺寸小至100纳米以下。邮票的机械性能和表面结构将被设计为经历热触发的地形变化，从而赋予表面的粘合性能变化。研究目标是：(1)识别机械性能可切换和表面能可调的形状记忆聚合物，用作接触印刷印章；(2)使用具有明确特征和特征阵列的图案化形状记忆印章来执行、模拟和优化地形切换、界面粘合和材料转移，(3)对经历热机械应力的特征和表面进行物理、化学和机械表征，以及(4)演示将薄膜添加接触印刷制成干净、无缺陷和高分辨率的有机发光二极管阵列。与其他图案化方法不同，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衬底，并且分辨率不受光衍射或材料扩散的限制。一个核心前提是，随着时间的推移，制造路径必须是准确和可靠的，没有难以克服的障碍阻碍了该技术的大面积采用。研究人员将解决可能限制该方法可伸缩性的问题，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.