Innovative Processes for Fabricating Three-Dimensional Ultrathin Foams with Enhanced Thermal Properties

二维(2D)材料的三维(3D)超薄泡沫在结构加固、热管理和储能等方面具有很高的应用潜力。然而，由于用现有的材料加工技术将泡沫的孔径和支撑壁厚度控制到所需尺寸的巨大困难，它们的工业应用受到了限制。该奖项通过研究一种原创和新颖的工艺来支持应对这一挑战的研究，该工艺可以导致具有可调孔尺寸的3D泡沫的高度可控增长。这项研究将加速3D多孔材料的加工技术，对包括储能、热管理和柔性电子在内的一系列应用产生重大影响。它还将为教育下一代劳动力提供机会，以增强美国在材料加工和制造技术方面的竞争力。这项研究的目的是探索一种创新的工艺来制造2D超薄石墨(UG)以及类似的2D六方氮化硼(h-BN)介质泡沫的3D泡沫结构，其孔径在1微米到100微米之间可控，支柱壁厚在1到1000 nm之间可调。该材料加工方法包括一种新的制备泡沫镍作为孔尺寸减小或多层孔隙率的催化模板的方法，一种能量有效和快速的射频感应加热方法来生长大规模的UG和h-BN材料，以及一种高效的镍刻蚀工艺。这项工作还将建立对孔尺寸、壁厚、晶界和结构对UG和h-BN泡沫和复合材料热性能影响的基本理解。将获得材料加工方面的新知识，用于制造具有增强热管理性能的三维多层多孔UG和h-BN材料。这项工作产生的理解和知识也可能导致将各种其他2D材料制造成3D泡沫结构的一般方法。

Three-dimensional (3D) ultrathin foams of two-dimensional (2D) materials hold high potential for a variety of applications, including structure reinforcement, thermal management, and energy storage. However, their industrial adoption has been limited due to the substantial difficulties in controlling the pore size and strut wall thickness of the foams to desired dimensions with existing materials processing technologies. This award supports research to address this challenge, by investigating an original and novel process that can lead to highly controllable growth of 3D foams with tunable pore sizes. This research will accelerate the processing technology of 3D porous materials with substantial impact on an array of applications including energy storage, thermal management, and flexible electronics. It will also provide opportunities for educating the next generation workforce to enhance the competitiveness of the US in materials processing and manufacturing technologies. The goal of this research is to investigate an innovative process for manufacturing 3D foam architectures of 2D ultrathin graphite (UG) as well as similar foams of dielectric 2D hexagonal boron nitride (h-BN) with controllable pore sizes between 1 micon and 100 microns, and tunable strut wall thickness from 1 to 1000 nm. The materials processing method consists of a new approach for fabricating Ni foams as catalytic templates with reduced pore sizes or multiple level porosity, an energy effective and rapid RF induction heating method for growth of large-scale UG and h-BN materials, and an efficient Ni etching process. This work will also establish a fundamental understanding of the effects of pore size, wall thickness, grain boundaries and structure on the thermal properties of UG and h-BN foams and composites. New knowledge in materials processing will be obtained for manufacturing 3D multilevel porous UG and h-BN materials with enhanced thermal management properties. The understanding and knowledge resulting from this work will also potentially lead to a general approach for manufacturing a variety of other 2D materials into 3D foam structures.