Rebar graphene.

As the cylindrical sp(2)-bonded carbon allotrope, carbon nanotubes (CNTs) have been widely used to reinforce bulk materials such as polymers, ceramics, and metals. However, both the concept demonstration and the fundamental understanding on how 1D CNTs reinforce atomically thin 2D layered materials, such as graphene, are still absent. Here, we demonstrate the successful synthesis of CNT-toughened graphene by simply annealing functionalized CNTs on Cu foils without needing to introduce extraneous carbon sources. The CNTs act as reinforcing bar (rebar), toughening the graphene through both π-π stacking domains and covalent bonding where the CNTs partially unzip and form a seamless 2D conjoined hybrid as revealed by aberration-corrected scanning transmission electron microscopy analysis. This is termed rebar graphene. Rebar graphene can be free-standing on water and transferred onto target substrates without needing a polymer-coating due to the rebar effects of the CNTs. The utility of rebar graphene sheets as flexible all-carbon transparent electrodes is demonstrated. The in-plane marriage of 1D nanotubes and 2D layered materials might herald an electrical and mechanical union that extends beyond carbon chemistry.

Graphene nanoribbons as an advanced precursor for making carbon fiber.

Graphene oxide nanoribbons (GONRs) and chemically reduced graphene nanoribbons (crGNRs) were dispersed at high concentrations in chlorosulfonic acid to form anisotropic liquid crystal phases. The liquid crystal solutions were spun directly into hundreds of meters of continuous macroscopic fibers. The relationship of fiber morphology to coagulation bath conditions was studied. The effects of colloid concentration, annealing temperature, spinning air gap, and pretension during annealing on the fibers' performance were also investigated. Heat treatment of the as-spun GONR fibers at 1500 °C produced thermally reduced graphene nanoribbon (trGNR) fibers with a tensile strength of 378 MPa, Young's modulus of 36.2 GPa, and electrical conductivity of 285 S/cm, which is considerably higher than that in other reported graphene-derived fibers. This better trGNR fiber performance was due to the air gap spinning and annealing with pretension that produced higher molecular alignment within the fibers, as determined by X-ray diffraction and scanning electron microscopy. The specific modulus of trGNR fibers is higher than that of the commercial general purpose carbon fibers and commonly used metals such as Al, Cu, and steel. The properties of trGNR fibers can be further improved by optimizing the spinning conditions with higher draw ratio, annealing conditions with higher pretensions, and using longer flake GONRs. This technique is a new high-carbon-yield approach to make the next generation carbon fibers based on solution-based liquid crystal phase spinning.

Large-area Bernal-stacked bi-, tri-, and tetralayer graphene.

Few-layer graphene, with Bernal stacking order, is of particular interest to the graphene community because of its unique tunable electronic structure. A synthetic method to produce such large area graphene films with precise thickness from 2 to 4 layers would be ideal for chemists and physicists to explore the promising electronic applications of these materials. Here, large-area uniform Bernal-stacked bi-, tri-, and tetralayer graphene films were successfully synthesized on a Cu surface in selective growth windows, with a finely tuned total pressure and CH(4)/H(2) gas ratio. On the basis of the analyses obtained, the growth mechanism is not an independent homoexpitaxial layer-by-layer growth, but most likely a simultaneous-seeding and self-limiting process.

Carbon nanotube and graphene nanoribbon-coated conductive Kevlar fibers.

Conductive carbon material-coated Kevlar fibers were fabricated through layer-by-layer spray coating. Polyurethane was used as the interlayer between the Kevlar fiber and carbon materials to bind the carbon materials to the Kevlar fiber. Strongly adhering single-walled carbon nanotube coatings yielded a durable conductivity of 65 S/cm without significant mechanical degradation. In addition, the properties remained stable after bending or water washing cycles. The coated fibers were analyzed using scanning electron microcopy and a knot test. The as-produced fiber had a knot efficiency of 23%, which is more than four times higher than that of carbon fibers. The spray-coating of graphene nanoribbons onto Kevlar fibers was also investigated. These flexible coated-Kevlar fibers have the potential to be used for conductive wires in wearable electronics and battery-heated armors.

A new class of functionalized polyoxometalates: synthesis, structure and preliminary antitumor activity studies of three arylimido substituted hexamolybdates bearing a strong electron-withdrawing nitro group, (Bu4N)2[Mo6O18([triple bond]NAr)] (Ar = 3-NO2-C6H4, 2-CH3-4-NO2-C6H3, 2-CH3-5-NO2-C6H3).

Three novel mono-functionalized arylimido derivatives of hexamolybdate bearing the strongest electron-withdrawing nitro group, (Bu(4)N)(2)[Mo(6)O(18)([triple bond]NAr)] (1, 2 and 3), have been synthesized for the first time by an improved reaction of octamolybdate ion and 3-nitroaniline hydrochloride, 2-methyl-4-nitroaniline hydrochloride and 2-methyl-5-nitroaniline hydrochloride respectively with DCC (N,N'-dicyclohexylcarbodiimide) as a dehydrating agent. Complete assignments were achieved for the title compounds by elemental analysis, IR, (1)H NMR, UV/visible and single-crystal X-ray diffraction analyses. The preliminary antitumor activity test indicated that the title compounds have some effects on the cellular growth inhibition of K562 cells.