Trapping Molecules in a Covalent Graphene-Nanotube Hybrid

This study employs molecular dynamics simulations to examine the physisorption behavior of hydrocarbon molecules on a covalent graphene-nanotube hybrid nanostructure. The results indicate that the adsorbed molecules undergo self-diffusion into the nanotubes without the need for external driving forces, primarily driven by significant variations in the binding energy throughout different regions. Notably, these molecules remain securely trapped within the tubes even at room temperature, thanks to a "gate" effect observed at the neck region, despite the presence of a concentration gradient that would typically hinder such trapping. This mechanism of passive mass transport and retention holds implications for the storage and separation of gas molecules.

Organically interconnected graphene flakes: A flexible 3-D material with tunable electronic bandgap

The structural and electronic properties of molecularly pillared graphene sheets were explored by performing Density Functional based Tight Binding calculations. Several different architectures were generated by varying the density of the pillars, the chemical composition of the organic molecule acting as a pillar and the pillar distribution. Our results show that by changing the pillars density and distribution we can tune the band gap transforming graphene from metallic to semiconducting in a continuous way. In addition, the chemical composition of the pillars affects the band gap in a lesser extent by introducing additional states in the valence or the conduction band and can act as a fine band gap tuning. These unique electronic properties controlled by design, makes Mollecular Pillared Graphene an excellent material for flexible electronics.

Controlling the electronic properties of 2D/3D pillared graphene and glass-like carbon via metal atom doping

We present the results of investigation of the nanopore filling of planar layered and bulk pillared graphene (PGR) as well as films and 3D samples of glass-like porous carbon (GLC) with potassium atoms. The patterns of charge transfer, electronic structure, and shift of the Fermi level during the filling of nanopores with potassium atoms are established. It is found that the greatest charge transfer from potassium atoms to the carbon framework is observed in PGR with a density of 1.1-1.4 g cm^-3 (that is, with a nanopore volume of 1300-1800 nm³) regardless of the framework topology. The maximum charge transfer occurs already when the mass fraction of potassium is 12 wt%. At the same potassium concentration, a maximum shift of the Fermi level to zero by ∼3 eV occurs in a bilayer PGR film with a density of 1.4 g cm^-3. Thus, our work shows for the first time that the electronic properties of nanoporous materials doped with alkaline earth metals (in particular, potassium) can be controlled by varying the volume of doped nanopores, i.e. by controlling the density of the nanoporous material. We first demonstrated that the potassium doping of PGR would be more effective than potassium doping of GLC. It is established that 2D samples of PGR and GLC completely reproduce the electronic properties of the bulk samples and even surpass them in some parameters. To carry out research, we developed a new method for nanopore filling with dopant atoms based on both the randomness of the nanopore filling and the energy advantage of this process. This method allows us to reliably determine the maximum possible mass fraction (wt%) of dopant atoms of any porous material.

Entropic selectivity in air separation via a bilayer nanoporous graphene membrane

Molecular dynamics simulations show that controlling the pore size and the pore shape via the bilayer nanoporous graphene membrane provides a novel way to enhance entropic selectivity for air separation via tumbling motion of the oxygen molecule.

Seawater desalination using pillared graphene as a novel nano-membrane in reverse osmosis process: nonequilibrium MD simulation study

Herein, the applicability and efficiency of two types of pillared graphene nanostructures, namely, (6,6)@G and (7,7)@G, were investigated as membranes in reverse osmosis seawater desalination using extensive nonequilibrium molecular dynamics simulations.

Nanolattices: An Emerging Class of Mechanical Metamaterials

In 1903, Alexander Graham Bell developed a design principle to generate lightweight, mechanically robust lattice structures based on triangular cells; this has since found broad application in lightweight design. Over one hundred years later, the same principle is being used in the fabrication of nanolattice materials, namely lattice structures composed of nanoscale constituents. Taking advantage of the size-dependent properties typical of nanoparticles, nanowires, and thin films, nanolattices redefine the limits of the accessible material-property space throughout different disciplines. Herein, the exceptional mechanical performance of nanolattices, including their ultrahigh strength, damage tolerance, and stiffness, are reviewed, and their potential for multifunctional applications beyond mechanics is examined. The efficient integration of architecture and size-affected properties is key to further develop nanolattices. The introduction of a hierarchical architecture is an effective tool in enhancing mechanical properties, and the eventual goal of nanolattice design may be to replicate the intricate hierarchies and functionalities observed in biological materials. Additive manufacturing and self-assembly techniques enable lattice design at the nanoscale; the scaling-up of nanolattice fabrication is currently the major challenge to their widespread use in technological applications.