Micro-Patterning Through Mechanics and Cracking of Drying Thin Films

这项资助的研究目标是阐明用于微图案化应用的溶剂填充薄膜的失效机理。溶胶凝胶等充满溶剂的薄膜系统在干燥过程中经常容易破裂，而且由于薄膜机械性能的变化，失效很难预测。在这项研究中，失效标准将通过两种专门为超薄膜研究量身定做的非接触式实验方法来确定：激光散裂附着力测试和基于荧光的数字图像相关测量。然后，实验结果将为有限元模型提供输入数据，以预测更复杂加载区域的破坏特征。一种基于力学的分析用于预测充满溶剂的薄膜系统的失效开始，将为利用微制造技术的多学科提供有价值的信息。特别是，这项工作将改进工业喷涂层应用的可靠性评估和失效预测。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了一种低成本技术。除了通过深入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INSPIRE计划的一个模块中，这是一个为当地高中生制定的暑期充实计划，面向目前在工程学领域没有代表性的群体。

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.