CAREER: Fundamental Investigation of Thin-Film Evaporation Using Crystalline Porous Inverse Opals

对于从现代电子设备到发电厂冷却的各种应用来说，通过相变过程(例如蒸发)来散热是一项艰巨的挑战。为此，纳米结构因其巨大的表面积和将工作液输送到蒸发表面的能力而引起了人们的极大兴趣。然而，到目前为止，由于纳米结构的复杂结构，确定其在相变过程中的作用一直是一项挑战。为了解决这个问题，这个职业项目将使用非常规则的多孔介质来研究薄膜蒸发物理。这种多孔介质的结构规律性将允许在材料的形式和蒸发换热之间建立新的关系。该项目的研究成果将纳入教育和外联活动，以提高公众对热运输现象的兴趣，并培训下一代研究人员。综合教育和外展计划将通过新的感官学习教育工具、研究和指导计划以及关于纳米级相变热传递主题的新研究生课程来解决。这个职业项目的科学目标是利用新的有序多孔介质在与结构相关的蒸发相变物理中发现新的发现。该项目的具体任务包括：(1)展示具有理想传输性能的亲水反蛋白石；(2)在孔级研究局部薄膜蒸发(目的是了解这种孔的球形凹面形状对薄膜蒸发的作用)；以及(3)检查设备中的换热性能。这些任务可以通过研究蛋白石模板的自组装和金属化，以及表面工程、多尺度计算模型和高保真测量来验证对蒸发性能的理解来完成。关于多孔介质传输物理的新发现将为下一代热管理设备的设计向前迈进一大步，例如利用新兴多孔材料的微流控通道、柔性冷却器和热管。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Dissipating extreme heat through phase change processes (e.g. evaporation) is a daunting challenge for various applications ranging from modern electronic devices to power plant cooling. For this purpose, nanoscale structures have drawn significant interest due to their large surface area and ability to deliver working fluid to evaporating surfaces. However, to date it has been challenging to identify the role of the nanostructures in phase change processes owing to their complex structures. To address this problem, this CAREER project will employ extremely regular porous media to investigate thin-film evaporation physics. The structural regularity of such porous media will allow new relationships to be developed between the form of the material and the evaporation heat transfer. The research outcomes from this project will be integrated into educational and outreach activities to promote public interest in thermal transport phenomena and train the next generation of researchers. The integrated educational and outreach plan will be addressed through new sensory learning educational tools, research and mentoring programs, and a new graduate course on nanoscale phase change heat transfer topics. The scientific objective of this CAREER project is to find new discoveries in structure-related evaporation phase change physics utilizing new classes of well-ordered porous media. The specific tasks of this project include (1) demonstrating hydrophilic inverse opals with desired transport properties; (2) studying local thin-film evaporation at the pore-level (with the aim of understanding the role of the spherical concave shape of such pores on thin-film evaporation); and (3) examining heat transfer performance in the devices. The tasks can be accomplished by studying the self-assembly and metallization of the opal template with surface engineering, multiscale computational models, and high-fidelity measurements to validate understanding of evaporation performance. The new discoveries about the transport physics through porous media will provide a big step forward for the design of next-generation thermal management devices such as microfluidic channels, flexible coolers, and heat pipes that leverage emerging porous materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.