Thickness, chirality and pattern dependence of elastic properties of hydrogen functionalized graphene

J Huang and CH Wong, COMPUTATIONAL MATERIALS SCIENCE, 92, 192-198 (2014).

DOI: 10.1016/j.commatsci.2014.05.047

Molecular dynamics simulations have been adopted to study the dependence of number of layers, chirality and hydrogen coverage on the mechanical properties of hydrogen functionalized graphene. We found out that increasing hydrogen coverage results in a drop in critical strain and ultimate strength. The addition of hydrogen atoms from 0% to 30% dramatically weakens the material. Beyond that limit, the critical strain showed less sensitivity to the variation of hydrogen coverage. Further increase in the number of hydrogen atoms results in another sharp decrease in the critical strain. Our results showed that the mechanical properties of hydrogen functionalized graphene depend on the chirality of the sample. Zigzag samples have higher critical strain compared to the armchair counterparts due to the difference in bond alignment between these two structures. In addition, increasing the number of layers produces a weakening effect on the overall mechanical performance in terms of critical strain. Additionally, we studied the mechanical properties of patterned hydrogen functionalized graphene and our results showed that the critical strain and ultimate strength are dependent on the edge geometry of the overall structure. The difference of the edge configuration of the inner graphene nano-ribbon (GNR) also leads to minor discrepancy of these two properties. Our work underlined the importance of considering the configuration of hydrogen functionalized graphene when designing hydrogen functionalized graphene for different applications. (C) 2014 Elsevier B.V. All rights reserved.

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