CAREER: Multi-Scale Study of Transport Phenomena in Printable Electronics for Enhanced Microstructure and Properties

0846825 y。该职业规划将通过创新研究和教育的结合，促进对柔性基板上喷墨印刷功能材料的传输过程的基本理解。该研究将新型模型和实验相结合，包括：(1)对喷墨沉积材料的润湿、蒸发和自组装相互作用引起的流动、传热和传质的原位观察和多尺度建模；（ii）激光和等离子体基板表面改性，以改善卷对卷（R2R）格式的沉积；（iii）沉积材料的显微组织和电-热力学性能表征。重点是在介观尺度上，可以直接观察到马兰戈尼流、蒸发和粒子自组装。建立晶格玻尔兹曼模型，直接模拟水滴在表面改性基板上的冲击和蒸发；粒子-粒子、粒子-载体液体和粒子-衬底相互作用；以及沉积颗粒材料的最终形态。与以往只关注沉积结构的死后分析的实验不同，该实验将集成超快共聚焦显微镜和微粒子图像测速系统，以实时监测蒸发阶段的粒子自组装，并提供模型验证。无掩模激光图案与等离子体蚀刻相结合，改变了衬底表面能，从而为受限沉积提供了润湿控制。由于烧蚀粗化，激光产生的具有增加表面积的图案将增强沉积材料的附着力。现代表征技术（例如，SEM， TEM， AFM，纳米压痕和红外显微镜）将用于确定沉积材料的最终微观结构以及电学，热学和机械性能。知识优势：在柔性基板上使用喷墨打印和直接激光图案的环境友好的R2R电子制造是一种使能技术，将提供所需的大批量，低成本的柔性电子产品生产。所提出的工作将对沉积材料的最终微观结构和性能如何取决于电子墨水配方、加工条件和衬底性能产生重要的理解。喷墨装置空间精度的固有限制、润湿、脱湿、接触线钉住、界面不稳定性、沉积液滴内的微流动以及液滴蒸发过程中颗粒物质的自组装都导致了沉积电子材料缺乏精确控制。预图案化的基材表面将提供喷墨材料的优先润湿和脱湿，以及更好的基材附着力。这将使更可靠的沉积模式具有更好的边缘清晰度，更高的分辨率，并改善可印刷电子和设备的电-热-机械性能。该项目还将影响涉及相变和粒子组装的复杂流体的其他研究前沿。更广泛的影响：该项目非常适合先进微电子制造中心的战略方向，该中心是宾厄姆顿的国家微电子R2R制造研发中心。从该项目中获得的知识将对可印刷电子产品的加工产生巨大影响，从低成本消费产品、太阳能电池、低功耗照明到高度专业化的小型传感器和医疗保健设备。综合教育计划旨在通过开发新课程来加强热流体科学教育，以突出研究生和本科生水平的多尺度建模和纳米尺度现象。作为所提出的计算建模工作的一个分支，将开发虚拟热流体实验室的课件。通过对当地中学的招募访问和与当地女工程师协会分会的参与，将持续努力吸引女性和其他未被充分代表的学生参加工程项目。可打印电子产品将在沃森工程师周开放日和宾厄姆顿探索中心的暑期科学营中展示。面向职业中期专业人员的柔性电子加工研讨会将着重于结构-性能-性能关系。与Endicott Interconnect在激光表面处理方面的合作将提供实习机会，并促进研究向创新的过渡。与新型油墨和承印物供应商（如康宁）的合作将使我们能够为每种特定应用定制油墨和承印物配方。PI和宾厄姆顿计算机科学学院的共同努力将通过与纽约州电网的合作来推进网格计算能力。

0846825Y. SunThis career plan will advance the fundamental understanding of transport processes of inkjet-printed functional materials on flexible substrates through the integration of innovative research and education. The proposed research combines novel modeling and experiments that include: (i) in-situ observation and multi-scale modeling of the flow, heat and mass transfer induced by the interplay of wetting, evaporation, and self-assembly of inkjet-deposited materials; (ii) laser and plasma substrate surface modification for improved deposition in a roll-to-roll (R2R) format; and (iii) microstructural and electrical-thermalmechanical property characterization of deposited material. The focus is on the mesoscopic scale, where Marangoni flow, evaporation, and particle self-assembly can be directly observed. A lattice Boltzmann model will be developed to directly simulate drop impact and evaporation on surface modified substrates; particle-particle, particle-carrier liquid, and particle-substrate interactions; and final morphology of deposited particulate materials. In contrast to previous experiments that have only been concerned with post-mortem analysis of deposited structures, the proposed experiments will integrate ultrafast confocal microscopy and micro-particle image velocimetry systems to monitor in real-time particle self-assembly during the evaporation phase and to provide model validations. The maskless laser patterning combined with plasma etching alters substrate surface energies and hence provides wetting controls for a confined deposition. The laser-created patterns with increased surface areas due to ablative roughening will enhance adhesion of the deposited materials. Modern characterization techniques (e.g., SEM, TEM, AFM, nano-indentation, and infrared microscopy) will be used to determine final microstructures as well as electrical, thermal, and mechanical properties of deposited materials.Intellectual Merit: Environmentally-benign R2R electronics fabrication using inkjet printing and direct laser patterning on flexible substrates is an enabling technology that will provide desired high-volume, low-cost production of flexible electronics. The proposed work will yield important understanding of how the final microstructure and properties of deposited materials depend on the electronic ink formulation, processing conditions, and substrate properties. The intrinsic limits on the spatial accuracy of ink-jetting devices, wetting, de-wetting, contact line pinning, interfacial instabilities, microflows within the deposited drop, and the self-assembly of particulate matter during drop evaporation all contribute to the lack of precise control of deposited electronic materials. The pre-patterned substrate surface will provide preferential wetting and dewetting of the inkjetted material and better substrate adhesion. This will enable more reliable deposition patterns with better edge definition, higher resolution, and improved electrical-thermal-mechanical properties of printable electronics and devices. This project will also impact other research frontiers on complex fluids involving phase change and particle assembly.Broader Impacts: This project is an excellent fit to the strategic directions of the Center for Advanced Microelectronics Manufacturing, a national microelectronics R2R manufacturing R&D center at Binghamton. Knowledge obtained from this project will have a dramatic impact on the processing of printable electronics, ranging from low-cost consumer products, solar cells, and low-power lighting to highly specialized small scale sensors and healthcare devices. The integrated education plan seeks to enhance thermo-fluid science education through the development of new courses to highlight multiscale modeling and nanoscale phenomena at both graduate and undergraduate levels. As an offshoot of the proposed computational modeling work, courseware for virtual thermo-fluid laboratories will be developed. Through recruiting visits at local secondary schools and involvement with the local Society of Women Engineers chapter, a sustained effort to attract women and other under-represented students in engineering programs will be made. Printable electronics will be demonstrated at the Watson Engineer's Week Open House and through Summer Science Camp at the Discovery Center in Binghamton. Seminars on the processing of flexible electronics for mid-career professionals will emphasize on the structureproperty-performance relationships. The partnership with Endicott Interconnect on laser surface treatment will enable internship opportunities and foster the research to innovation transition. The collaboration with novel ink and substrate providers (e.g., Corning) will allow us to customize ink and substrate formulas for each specific application. The joint effort between the PI and Computer Science faculty at Binghamton will advance the grid computing capability via the partnership with the New York State Grid.