Highly curved carbon nanostructures produced by ball-milling

The formation of nanoarches or highly curled carbon nanostructures during high-energy ball-milling of graphite is reported. High-resolution transmission electron microscopy indicates that graphite sheets with a thickness of less than 10 nm (dimension along the c-axis) hold high flexibility and are highly bendable, thus forming nanoarches or highly curved nanostructures upon ball-milling. It is evident that these nanostructures are formed by bending the flat sp2 layers directly under the mechanical deformation.