ISS: Collaborative Research: Examination of the Multi-physical Properties of Microgravity-synthesized Graphene Aerogels

石墨烯是一种二维（2D）形式的碳，自2004年发现以来，由于其惊人的电气，机械和热性能而引起了极大的兴奋。然而，实现石墨烯的大规模可制造性的困难阻碍了石墨烯在纳米电子、电池、传感和复合材料等目标应用中的大规模采用。石墨烯气凝胶是一类由共价交联成三维（3D）结构的2D石墨烯片制成的材料，在很大程度上保留了其石墨烯构建块的许多非凡特性，但尺寸仅受合成过程中使用的容器的限制。在这项工作中，将研究在重力（地球上）和微重力（国际空间站，ISS）条件下石墨烯基水凝胶的合成。通过在国际空间站上进行微重力实验，重力驱动的过程，如沉降和浮力驱动的对流将受到阻碍，而有助于石墨烯气凝胶组装的潜在现象（例如，随机布朗运动）将被隔离和研究的第一次。这项合作计划还旨在接触小学生、本科生、研究生和公众，以提高对纳米技术和航空航天工程领域以及学术界职业的认识。 为了扩展空间生产气凝胶的知识，我们将比较微重力合成的石墨烯气凝胶与地球合成的气凝胶的性质。目标有两个方面：（1）研究在重力存在下石墨烯气凝胶（GA）合成的生长行为（交联、附聚、干燥）;以及（2）检查并解释基于微重力的合成对GA的三维（3D）介观结构和多物理性质（热传输、机械行为和电学特性）的影响。 最终，这项工作将为石墨烯气凝胶（和其他气凝胶）的工程设计提供基础，这些气凝胶具有高度均匀的微观结构和相应的上级电气，机械和热性能，以实现各种各样的地球和空间应用，例如超轻质结构材料，超级电容器和电池电极，储氢和水处理膜。此外，在国际空间站上进行气凝胶的太空生产，可以使国际空间站的研究人员直接使用材料和设备，并用于未来的太空任务。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Graphene, a two-dimensional (2D) form of carbon, has generated extreme excitement since its discovery in 2004, due to its startling electrical, mechanical, and thermal properties. Yet, difficulties in realizing large-scale manufacturability of graphene has hindered mass adoption into target applications such as nanoelectronics, batteries, sensing and composites. Graphene aerogels, a class of materials made of 2D graphene sheets covalently crosslinked into a three-dimensional (3D) structure, largely retain many of the extraordinary properties of their graphene building blocks but are limited in size only by the container used during synthesis. In this work, graphene-based hydrogel synthesis in gravity (on Earth) and microgravity (on the International Space Station, ISS) conditions will be examined. Through experimentation in microgravity on the ISS, gravity-driven processes such as sedimentation and buoyancy-driven convection will be hindered, and underlying phenomena contributing to graphene aerogel assembly (e.g., random Brownian motion) will be isolated and investigated for the first time. This collaborative program also aims to reach elementary school students, undergraduate students, graduate students and the general public to raise awareness of the fields of nanotechnology and aerospace engineering, as well as careers in academia. To extend the knowledge of space-produced aerogel, we will compare the properties of microgravity-synthesized graphene aerogels to Earth-synthesized aerogels. The objectives are two-fold: (1) to study the growth behavior (cross-linking, agglomeration, drying) of graphene aerogels (GA) synthesis outside the presence of gravity; and (2) to examine and explain the influence of microgravity-based synthesis on the 3-dimensional (3D) mesostructure and multi-physical properties (thermal transport, mechanical behavior, and electrical characteristics) of GAs. Ultimately, this work will provide the foundation for engineering of graphene aerogels (and other aerogels) with highly homogenous microstructures and correspondingly superior electrical, mechanical, and thermal properties to enable a wide variety of Earth and space applications, such as, ultra-lightweight structural materials, supercapacitor and battery electrodes, hydrogen storage, and water treatment membranes. In addition, in-space production of aerogels on the ISS may enable direct use of materials and devices by ISS researchers and for future space missions.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.