ISS: Synthesis of Electrically Conductive High-Temperature Composites Under Microgravity and Normal Gravity Conditions

随着空间探索的快速推进，在空间进行材料研究已成为主流。与此同时，新型二维材料和聚合物衍生的高温陶瓷引起了材料界的关注。在这个研究项目中，二维MXene将被整合到碳化硅氧基体中，以在地球和国际空间站上产生新的材料。系统地比较了二维材料和聚合物在微重力条件下向陶瓷转化的高温演化行为。这些材料有望具有高抗氧化性、优异的导电性和低密度。它们还应该在韧性、强度和高温稳定性方面具有很大的协同潜力。复合材料可以根据应用需要制成几乎任何形状（大块、涂层、离散特征等）和尺寸（纳米到宏观）。此外，这些材料可以很容易地生产复杂形状、薄壁或自由形状的部件，在高温环境中具有轻量级和功能性。这项研究将引领新一代的先进材料，这些材料在热交换器、电力系统、催化剂支撑、能量存储、电极、纳米器件和微系统等方面具有巨大的潜力。最终，项目成果将带来新的应用，使空间科学和地球上的生命受益。研究生和本科生都将参与研究项目。PI将把目前的活动扩展到弗吉尼亚州东部，同时继续在校园举办不同的夏令营。此外，PI将扩大与西弗吉尼亚科学博物馆的联系，以激发女性和少数民族对科学和工程的兴趣。该研究项目将促进对不同重力条件下原子和纳米级物质相互作用的理解，以探索一类新的高温稳定和导电材料。高温复合材料将包括致密和多孔微观结构，但所开发的方法将适用于广泛的由2D添加剂和聚合物前体衍生的高温材料。本课题有望为聚合物衍生陶瓷的原子水平设计和热力学预测提供新理论、新知识和新方法。这个项目的结果将为利用微重力来理解和创造新的高温材料开辟新的机会。该团队将使用四种方法进行研究。首先，利用MXene剥离和表面功能化，在500-700°C进行预热解，为微重力和地球重力研究提供受控状态。其次，在地球和微重力条件下进行不同气氛热解，了解气氛和气体释放对新相形成的影响。第三，将理论热力学计算与实验热解研究相结合，探索基本的界面相互作用和相演化过程。最后，将全面研究重力对二维MXene在热解过程中的变形、堆积以及与碳化硅的化学相互作用的影响；在不同重力条件下，孔隙系统的相和结构演化与孔隙稳定性和收缩/坍塌有关。教育部分是培训多名研究生和本科生，重点是妇女和少数民族。PI将把目前的活动扩展到弗吉尼亚州东部，同时继续在校园举办不同的夏令营。此外，PI将扩大与西弗吉尼亚科学博物馆的联系，以激发女性和少数民族对科学和工程的兴趣。该奖项反映了美国国家科学基金会的法定使命，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。

With the fast advancement of space exploration, conducting materials research in space is becoming mainstream. At the same time, novel two-dimensional materials and polymer derived high temperature ceramics have captured the attention of the materials community. In this research project, two dimensional MXene will be incorporated into a silicon oxycarbide matrix to generate new materials, both on Earth and at the International Space Station. The high temperature evolution behaviors of two-dimensional materials and polymer to ceramic conversion under microgravity conditions will be systematically compared with the processes on Earth. These materials are expected to have high oxidation resistance, excellent electrical conductivity, and low density. They should also have great synergistic potentials for toughness, strength, and high temperature stability. The composites can be made into almost any shape (bulk, coating, discrete feature, et cetera) and size (nano- to macro-) based on application needs. In addition, these materials can easily produce complex shape, thin-wall, or freeform components with lightweight and functional capabilities in high temperature environments. This research will usher in a new generation of advanced materials which have great potential to be used as heat exchangers, electric systems, catalyst support, energy storage, electrodes, nano-devices, and microsystems. Ultimately, project results will lead to new applications benefiting space science and life on Earth. Both graduate and undergraduate students will be involved in the research project. The PI will expand current activities to Eastern Virginia while continuing efforts with different summer camps on campus. In addition, the PI will expand outreach efforts to the Western Virginia Science Museum to stimulate the interest of females and minorities in science and engineering.This research project will advance understanding of atomic- and nano-level species interactions under different gravitational conditions in order to explore a new class of high temperature stable and electrically conductive materials. The high temperature composites will include both dense and porous microstructures but the methodology developed will be applicable to a wide range of high temperature materials derived from 2D additives and polymer precursors. This research project is expected to develop new theories, provide new knowledge, and offer novel methods in atomic level design and thermodynamic prediction of polymer derived ceramics. Results from this project will open new opportunities for using microgravity to understand and create novel high temperature materials. The team will conduct the research using four approaches. First, using MXene exfoliation and surface functionalization, pre-pyrolysis at 500-700°C will be conducted in order to provide controlled states for microgravity and Earth gravity studies. Second, different atmosphere pyrolysis will be conducted on Earth and under microgravity to understand the atmosphere and gas release effects on new phase formation. Third, theoretical thermodynamic calculation and experimental pyrolysis studies will be combined in order to explore the fundamental interfacial interaction and phase evolution processes. Finally, gravitational effects on 2D MXene deformation, stacking, and chemical interaction with silicon oxycarbide during pyrolysis will be comprehensively investigated; the phase and structural evolution of the porous systems will be correlated with pore stability and shrinkage/collapse under different gravity conditions. The educational component is training of multiple graduate and undergraduate students, with a focus on women and minorities. The PI will expand current activities to Eastern Virginia while continuing efforts with different summer camps on campus. In addition, the PI will expand outreach efforts to the Western Virginia Science Museum to stimulate the interest of females and minorities in science and engineering.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.