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Chemically modified graphene films with tunable negative Poisson's ratios
Yeye Wen1, Enlai Gao2, Zhenxing Hu3
1Department of Chemistry, MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Tsinghua University, Beijing, 100084, China.
Nature Communications
|June 6, 2019
Summary
Chemically modified graphene films exhibit a negative Poisson
Area of Science:
- Materials Science
- Nanotechnology
- Mechanical Engineering
Background:
- Graphene assemblies possess hierarchical structures enabling unique material properties.
- Surface and interfacial functionalization are key to unlocking unconventional material behaviors.
Purpose of the Study:
- To investigate the origin of negative Poisson's ratios in chemically modified graphene films.
- To demonstrate methods for controlling and tuning these negative Poisson's ratios.
Main Methods:
- Experimental characterization of graphene film microstructures (wrinkles, delamination, stacks).
- Theoretical analysis to validate proposed mechanisms for negative Poisson's ratios.
- Application of pre-stretching and modulation of wavy textures to control material properties.
Main Results:
- Graphene films exhibited significant negative Poisson's ratios (-0.25 to -0.55) due to microstructural hierarchy.
- Pre-stretching and texture modulation allowed for controlled and finely-tuned negative Poisson's ratios.
- Mechanism linking microstructure to auxetic behavior was validated.
Conclusions:
- Microstructural design is crucial for achieving negative Poisson's ratios in 2D material films.
- Chemically modified graphene films offer a platform for developing materials with tunable auxetic properties.
- Findings provide insights for designing mechanomutable materials from two-dimensional building blocks.