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

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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.