Fabrication of reduced graphene oxide/chitosan composite fiber by dry-jet wet spinning

Reduced graphene oxide (rGO) which was nontoxic, reduced from graphene oxide (GO), and decorated was mixed with chitosan (CS) solution to prepare rGO/chitosan (rGO/CS) biocomposite fiber by dry-jet wet spinning. rGO-/genipin-cross-linked CS (rGO/GCS) composite fiber was prepared. The conditions on nontoxic reduction of GO, namely decoration, spinning, drawing, and nontoxic cross-linking, were studied and optimized. The way to disperse rGO homogeneously in spinning solution was discussed. After surface decorating, rGO was covered by CS without reunion. No phase separation in rGO/CS spinning solution was observed. The solution remained stable for a week after being diluted. The decoration of CS was an effective way to achieve homogeneous dispersion of rGO in solution for spinning. Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and fluorescence spectroscopy were used to characterize the fibers and their precursors. A series of rGO/CS fibers with a diameter of 0.1 mm were successfully fabricated. The well-dispersed and exfoliated rGO nanosheets were assembled in CS matrix. Both rGO/CS fibers and rGO/GCS fibers maintained the intrinsic fluorescence. Both uncross-linked and cross-linked composite fibers could be bent freely. The work built up the foundation for systematic conductivity and mechanical property research about rGO/CS composite fibers.