Dye Probe Studies of Spin Coating of Sol-Gel Solutions

溶胶-凝胶溶液旋涂的染料探针研究

• 批准号: 9802334
• 负责人: Dunbar Birnie
• 金额: $ 28.37万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2004-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9802334&HistoricalAwards=false
• 关键词: Dye; Probe; Studies; Spin; Coating; Dye; Probe; Studies; Spin; Coating

9802334 Birnie Sol-gel chemistry is a popular technique for making new materials and high technology coatings of a wide variety of types. Because of the ever-expanding importance of sol-gel synthesis, and because of the need to make high quality coatings with a high- throughput industrial procedure, it is important to understand the fundamentals of spin coating when performed using sol-gel solutions. This project will monitor and understand, in real time, the coating formation and drying of sol-gel solutions during spin coating. Dye molecules will be incorporated into the sol-gel solutions to help sense the chemical and physical changes taking place during spin coating. Two fundamental processes are critical in controlling coating formation during spin coating in general: 1) viscous flow and 2) evaporation. Early stages are dominated by the viscous behavior, i.e. relatively smooth fluid flow radially outward on the substrate. As the fluid layer gets thinner the outward flow rate reduces until the second process (evaporation) takes over as the dominant process. This transition corresponds to a "setting" point for coating formation. When spin coating is performed on sol-gel solutions then extra complexities arise including accelerated chemical reaction caused by solvent evaporation and viscosity changes being driven by the hydrolysis and condensation reactions in solution. Thus, sol-gel solutions may be particularly sensitive to the conditions that are imposed by the spin coating process. Carefully designed optical measurements will be carried out which would allow in-depth study of the dynamical and chemical effects that are occurring in sol-gel solutions during spin coating. Small concentrations of dye molecules would be incorporated into the sol-gel solutions for use as structure/chemistry probes during the spinning process. The primary focus will be on molecules that change their absorption spectra depending on the characteristics of the local envir onment. Therefore, equipment would be set up to allow absorption characteristics to be measured during spin coating processing. In addition, laser interferometry would be used to dynamically monitor the rapid fluid thinning process occurring during spinning. %%% It is anticipated that increased understanding of this important technological process would lead to new methods for improving the quality of spin coated sol-gel layers, thus allowing the production of materials with higher reliability and increased manufacturing yield. For example, since the evaporation of the most volatile solution component will dominate during coating formation, then sol-gel scientists would learn to focus particularly close attention to the chemical effects caused by early and rapid removal of this component, especially with respect to premature gelation. And conversely, since the chemical condensation reactions can cause profound viscosity changes, then coating developers would seek to understand more about the rheological characteristics of their sol-gel solutions, even before coating quality issues arise. ***

9802334 Birnie Sol-Gel Chemistry是一种流行的技术，用于制造各种类型的新材料和高科技涂料。 由于Sol-Gel合成的重要性不断扩大，并且由于需要使用高吞吐量工业程序进行高质量的涂料，因此使用Sol-Gel Solutions进行旋转涂层的基础知识很重要。 该项目将在自旋涂层期间实时监测和理解溶胶 - 凝胶溶液的涂料形成和干燥。 染料分子将被掺入溶胶 - 凝胶溶液中，以帮助感知自旋涂层期间发生的化学和物理变化。 通常，两个基本过程对于控制自旋涂层期间的涂层形成至关重要：1）粘性流动和2）蒸发。 早期阶段由粘性行为（即底物上径向向外流动流动）主导。 随着流体层的变细，向外流速降低，直到第二个过程（蒸发）接管为主要过程。 该过渡对应于涂层形成的“设置”点。 当对溶胶 - 凝胶溶液进行自旋涂层时，会产生额外的复杂性，包括由溶剂蒸发和粘度变化引起的加速化学反应，由溶液中的水解和凝结反应驱动。 因此，Sol-Gel溶液可能对自旋涂层过程施加的条件特别敏感。 将进行精心设计的光学测量，这将允许对旋转涂层期间溶胶 - 凝胶溶液中发生的动力学和化学作用进行深入研究。 在旋转过程中，将少量的染料分子掺入Sol-Gel溶液中作为结构/化学探针。 主要的重点将放在分子上，这些分子会根据局部环境的特征来改变其吸收光谱。 因此，将设置设备以允许在自旋涂层处理过程中测量吸收特性。 此外，激光干涉法将用于动态监测旋转过程中发生的快速流体变薄过程。 %%％预计，对这一重要技术过程的了解会增加，这将导致改善旋转涂层的溶胶 - 凝胶层质量的新方法，从而允许生产具有更高可靠性并提高制造产量的材料。 例如，由于最挥发性溶液组件的蒸发在涂层形成过程中将主导，因此Sol-Gel科学家将学会集中精力密切关注该成分的早期和快速去除引起的化学效应，尤其是在过早凝胶化方面。 相反，由于化学凝结反应会导致粘度发生深刻的变化，因此涂料开发人员甚至在出现涂层质量问题之前就会寻求更多地了解其Sol-Gel Solutions的流变特性。 ***