A facile route for the large scale production of graphene oxide(GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates.Significant enhancement in mechanical stiffness(341%) and fracture strength(234%) of GO paper have been achieved upon modification with a small amount(less than 10 wt%) of glutaraldehyde(GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.
A novel,simple,and effective one-step method has been developed to cut the conventional long and entangled multi-walled carbon nanotubes(MWCNTs) with nanoscissors.The cutting process was carried out by the interactive collision of CNTs with the silicon carbide particles adhered on the abrasive papers.The final cut nanotubes have an average length of 200~300 nm.The statistical length distribution result indicates that cutting by this method achieves high cutting efficiency for short duration of 2 min.Shortened nanotubes are found to be easily dispersed into aqueous and ethanol solutions.The cut MWCNTs/copper composite thin film fabricated by combined electrophoresis and electroplating techniques reveals that MWCNTs after cutting are well distributed and adhered to the Cu matrix.This method is not only fast and efficient but also no chemical waste,which will expand many potential applications of CNTs.
Graphene, as an intermediate phase between fullerene and carbon nanotube, has aroused much interests among the scientific community due to its outstanding electronic, mechanical, and thermal properties.With excellent electrical conductivity of 6000 S/cm, which is independent on chirality, graphene is a promising material for high-performance nanoelectronics, transparent conductor, as well as polymer composites. On account of its Young's Modulus of 1 TPa and ultimate strength of 130 GPa, isolated graphene sheet is considered to be among the strongest materials ever measured. Comparable with the single-walled carbon nanotube bundle,graphene has a thermal conductivity of 5000 W/(m·K), which suggests a potential application of graphene in polymer matrix for improving thermal properties of the graphene/polymer composite. Furthermore, graphene exhibits a very high surface area, up to a value of 2630 m^2/g. All of these outstanding properties suggest a wide application for this nanometer-thick, two-dimensional carbon material. This review article presents an overview of the significant advancement in graphene research: preparation, functionalization as well as the properties of graphene will be discussed. In addition, the feasibility and potential applications of graphene in areas, such as sensors, nanoelectronics and nanocomposites materials, will also be reviewed.
