Temperature Dependence of Interfacial Bonding and Configuration Transition in Graphene/Hexagonal Boron Nitride Containing Grain Boundaries and Functional Groups

Mechanical Mechanism of Ion and Water Molecular Transport through Angstrom-Scale Graphene Derivatives Channels: From Atomic Model to Solid-Liquid Interaction

Ion and water transport at the Angstrom/Nano scale has always been one of the focuses of experimental and theoretical research. In particular, the surface properties of the angstrom channel and the solid-liquid interface interaction will play a decisive role in ion and water transport when the channel size is small to molecular or angstrom level. In this paper, the chemical structure and theoretical model of graphene oxide (GO) are reviewed. Moreover, the mechanical mechanism of water molecules and ions transport through the angstrom channel of GO are discussed, including the mechanism of intermolecular force at a solid/liquid/ion interface, the charge asymmetry effect and the dehydration effect. Angstrom channels, which are precisely constructed by two-dimensional (2D) materials such as GO, provide a new platform and idea for angstrom-scale transport. It provides an important reference for the understanding and cognition of fluid transport mechanism at angstrom-scale and its application in filtration, screening, seawater desalination, gas separation and so on.

Topological defects and nanoholes in graphene oxide/hexagonal boron nitride heterostructures: stress buildup and accumulation

The built-in distorted stress field of graphene (Gr) and its derivatives in defective state will induce local geometrical buckling due to the geometry of monatomic layer. The random distribution and types of functional groups (FGOs) and defects will have a significant impact on the stress accumulation and geometrical deformation of two-dimensional (2D) materials. By using molecular dynamics (MD), structure design and nonlinear mechanics theory, a new model (combining both planar 2D heterostructures and graphene oxide (GO)) was established to study geometrical effects, stress accumulation, bonding energies and mechanical properties of 2D interface (key point) at stress distortion field and accumulated stress field. The results show that grain boundaries (GBs), nanoholes and FGOs have different effects on the mechanical properties and out-of-plane deformation of 2D materials. By using Von-mises stresses and statistical mechanics, the geometrical effects, built-in distortion stress transfer and attenuation appeared in the each domain of 2D materials during the order-disorder transition processes. Moreover, there are two opposite aspects of stress accumulation, transmission, attenuation and geometrical effects of grain boundary (GBs), FGOs and nanoholes with distance. The ratio of strain energy (bond length and angle) is very sensitive to each domain of 2D materials. Finally, the 2D planar configuration gradually changes to a negative Gaussian surface, and the softening and weakening effects induced by GBs, nanoholes and FGOs are gradually enhanced. It is hoped that the current results can be used as a guide to adjust the geometry and stress accumulation of 2D materials in the new growth point.