Ultra-robust and high-toughness graphene oxide papers via synergistic strengthening by addition of carbon-nanotubes and copper ions.

Inspired by the excellent mechanical reinforcement effect of carbon nanotubes (CNTs) and the strong interactions between metal ions and graphene oxide (GO), ultra-robust, and high-toughness GO papers were fabricated via the synergistic reinforcement of CNTs and copper ions (Cu2+). The freestanding and flexible CNT/GO nanocomposite papers with a layered structure were readily fabricated by the vacuum-assisted filtration. After being cross-linked by a trace amount of copper ions (Cu2+), the tensile strength, elastic modulus and toughness of the modified GO papers increase 409.7%, 81.5% and 188.2%, respectively, when compared with the pure GO papers. It is revealed by scanning electron microscope and in situ Raman spectroscopy analysis that the CNTs and Cu2+ hindered the interlayer slippage between the GO sheets and promoted the stress transfer during the tensile loading. Considering the tunable and versatile properties of this hybrid carbon nanomaterial, this study will open an avenue for integrating rGO or GO papers to various applications. Image 1 [ABSTRACT FROM AUTHOR]