Designing and Processing Microstructurally Tailored Graphene Aerogels with An Understanding of Deformation and Failure Mechanisms

石墨烯气凝胶是世界上最轻的材料之一。它由聚集的石墨烯薄片组成的多孔网络组成，具有优异的机械、电子和导热性能。石墨烯气凝胶在可伸缩电子学、磁致动弹性体、电化学催化、隔热、超高效吸能器等领域具有广阔的应用前景。石墨烯气凝胶的结构完整性和功能性很难同时实现，这阻碍了其实际应用。了解变形机理对工程设计具有重要意义。石墨烯气凝胶具有不同于大多数其他结构和功能材料的多孔结构，因此显示出明显的变形现象。该奖项支持对石墨烯气凝胶在极端压缩下的独特变形的基础研究。研究获得的知识将为石墨烯气凝胶轻质材料的设计提供见解。这一努力将促进石墨烯气凝胶的应用，并使美国经济和社会受益。研究成果将被整合到本科教育的高级设计课程中，以开放式项目强调轻质材料的应用。石墨烯气凝胶与传统材料的主要区别在于其独特的微观结构，在变形过程中起着关键作用。本研究的总体目标是通过定制微观结构、粗粒度建模、重复压缩实验和微观观察来探索微观结构对石墨烯气凝胶变形机制的影响。我们将系统地研究微观结构对变形机制的影响，以了解石墨烯气凝胶在反复极端压缩下的形态、几何形状和排列方式如何影响石墨烯气凝胶的有效强度和可压缩性。我们将合成具有可控厚度的石墨烯气凝胶、纳米金属增强材料和定向排列的材料。通过原位和非原位微观表征，研究了施加加载顺序时的形貌演变。将通过执行具有新潜力的粗粒度模拟来构建主导变形机制图和力学性能的标度律。这项工作将有助于更好地了解石墨烯气凝胶中微观结构对变形机制的影响，并将推动微结构材料的现代设计和制造。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。

Graphene aerogel is one of the world's lightest materials. It consists of a porous network of aggregated graphene sheets and features excellent mechanical, electronic, and thermal conductivity properties. Graphene aerogel is promising for wide applications in stretchable electronics, magnetic actuated elastomers, electrochemical catalysis, thermal insulation, and ultra-efficient energy absorber. The practical implementation of graphene aerogel is hindered by the fact that the structural integrity and functionality are difficult to achieve simultaneously. Understanding deformation mechanisms is of primary importance for engineering design. Graphene aerogel displays distinguishable deformation phenomena due to its porous structure that is different from most of the other structural and functional materials. This award supports a fundamental study of the distinct deformation in graphene aerogel under extreme compression. The knowledge obtained from the research will provide insights for the design of graphene aerogel-based lightweight materials. The effort will promote the application of graphene aerogel and benefit the U.S. economy and society. The research results will be integrated into the senior design classes for undergraduate education with open-ended projects emphasizing the application of lightweight materials. The major difference of graphene aerogel from a conventional material is its unique microstructure that plays a pivotal role in deformation. The overall objective of the research is to explore how microstructure affects deformation mechanisms in graphene aerogel through tailoring microstructure, coarse-grained modeling, repeated compression experiments, and microscopic observations. A systematic study of microstructural effect on deformation mechanisms will be conducted to understand how the morphology, geometry, and alignment of individual building blocks affect the effective strength and compressibility of graphene aerogel under repeated extreme compression. Graphene aerogel with controlled thickness of its building blocks, nanopetal reinforcements, and aligned orientations will be synthesized. The evolution of morphologies with applied loading sequences will be studied by using in situ and ex situ microscopic characterizations. Maps of dominant deformation mechanisms and scaling laws for mechanical properties will be constructed by performing coarse-grained simulations with a new potential. The work will lead to a better understanding of microstructural effect on deformation mechanisms in graphene aerogel and will advance modern design and manufacturing of micro-architected 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.