Controlled assembly of graphene oxide nanosheets within one-dimensional polymer nanostructure.

We have demonstrated that the location and distribution of graphene oxide nanosheets (GONs) confined in 1D polymer composites were readily controlled depending on the processing conditions of electrospinning such as the types of polymers and the solvents used for the fabrication. The uniform bead-free poly(vinyl alcohol) (PVA)/GON composite nanofibers (NFs) even at high GON loading were obtained from the homogeneous polymer solutions attributable to the favorable interactions, as elucidated by spectroscopic data, thereby showing significant enhancement of their physical properties. The GONs were localized in the surface regions of the PVA-NFs due to the rapid convective evaporation of the water molecules, with concomitant aggregation into several sheets (<10 layers). In contrast, the co-continuous internal morphology of PVA/GON-NFs was constructed using less-volatile, polar dimethylformamide (DMF) solvents. Furthermore, the GONs were uniformly distributed in the more compatible polymer matrices such as polyacrylonitrile (PAN) and polystyrene (PS). Therefore, the distribution of GONs in 1D nanofibers was governed by the kinetics of solvent evaporation and the interaction with the polymer matrices.