Micro-Patterning Through Mechanics and Cracking of Drying Thin Films

本基金的研究目的是阐明用于微图案化应用的溶剂填充薄膜的失效机理。 溶剂填充的薄膜系统如溶胶-凝胶在干燥过程中经常容易破裂，并且由于薄膜机械性能的变化而难以预测失效。 在这项研究中，失效标准将通过两种专门针对超薄膜研究的非接触式实验方法来确定：激光喷涂附着力测试和基于荧光的数字图像相关测量。 实验结果将为有限元模型提供输入数据，以预测更复杂加载状态下的失效特性。 一个基于力学的分析，预测故障发生的溶剂填充薄膜系统将提供有价值的信息，利用微细加工技术的多个学科。 特别是，这项工作将提高工业喷涂应用的可靠性评估和故障预测。 此外，控制薄膜裂纹形成、宽度和密度的能力将为潜在的变革性微图案化方法提供基础，为创建分层分布的微尺度网络提供低成本技术。 除了通过密集的研究经验为研究生和本科生提供教育发展机会外，这项工作还将被整合到路易斯维尔大学的INSPIRE计划模块中，该计划是针对目前在工程学中没有代表的群体的当地高中生的既定夏季充实计划。

The research objective of this grant is to elucidate failure mechanisms of solvent-filled thin films for use in micro-patterning applications. Solvent-filled thin film systems such as sol-gels are frequently vulnerable to cracking during the drying process, and failure is difficult to predict due to evolving film mechanical properties. In this study, failure criteria will be determined via two non-contact experimental methods specifically tailored towards ultra thin film studies: laser spallation adhesion tests and fluorescence-based digital image correlation measurements. Experimental results will then provide the input data for a finite-element model to predict failure characteristics for more complicated loading regimes. A mechanics-based analysis for predicting failure onset for solvent-filled thin film systems will provide valuable information to the multiple disciplines that utilize microfabrication techniques. In particular, this work will improve reliability assessment and failure prediction for industrial spray coating applications. Additionally, the ability to control thin film crack formation, width, and density will provide the foundation for a potentially transformative micro-patterning method, offering a low-cost technique for creating hierarchically distributed micro-scale networks. In addition to providing educational development opportunities for both graduate and undergraduate students through intensive research experiences, this work will be integrated into a module for the INSPIRE Program at the University of Louisville, an established summer enrichment program for local high school students targeted towards groups currently unrepresented in engineering.