Fig. 3: Covalent linking of graphene edges by aromatic amide.
From: Covalently bridging graphene edges for improving mechanical and electrical properties of fibers
a Solid-state 13C cross-polarization NMR spectrum of the amide-connected GO fiber. b XPS C 1s spectra of freeze-dried GO and the amide-connected GO fiber, (c) N 1s spectrum of the optimal amide-connected GO fiber. To label the type of N, data for fibers fabricated with excess of amine and aliphatic ammonium salt are also shown. d Optical images of the amide-connected GO fiber swelling in NMP in the axial and stacking directions; right panel: XRD patterns of the fibers. The anisotropic swelling and the longer time confirm the presence of selective amide linkages at edges and enhanced π-π interactions. Error bars correspond to the statistical error from independent measurements from at least 15 locations. e Sheet size distribution comparison from laser diffraction measurement of the colloid of delaminated sheets from the swollen amide-bridged GO fiber and pristine GO.
