Negative Poisson's ratio in periodic porous graphene structures

We conducted molecular statics simulations to investigate the negative Poisson's ratio (auxetic behavior) of periodic porous graphene structures based on the rotating rigid unit mechanism. To obtain a negative Poisson's ratio, simple voids were periodically introduced into graphene. We showed that the Poisson's ratio of the designed graphene structure is strongly dependent on the aspect ratio of the voids, and it can approach the theoretical limit of -1.0. More importantly, the graphene periodic structure maintains its auxetic behavior even under large strains (epsilon similar to 0.20). Hence, it can be employed in a wide range of applications requiring structures that can endure large deformation. In addition, we found that the key factor in the auxeticity of the investigated structures is the deformation occurring at the void tips. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim