Fabrication, optimization and characterization of electrospun poly(caprolactone)/gelatin/graphene nanofibrous mats.

Recently graphene-based materials have been exploited widely in graphene-polymer nanocomposites and hold notable potential for various applications. In this study novel graphene-incorporated poly(caprolactone)/gelatin nanofibrous web were produced by electrospinning technique using acetic acid as a cost-effective eco-friendly solvent. Response surface methodology was used for optimizing the diameter of the electrospun nanofibrous web. To tailor electrospun nanofibers with suitable mechanical and electrical properties, the impact of affecting electrospinning parameters was studied. Our results show that, with increasing the PCL/gelatin ratio, the diameter of nanofibers increases, whereas increasing graphene concentration decreased the diameter of nanofibers up to an optimum content. With the incorporation of 1.5% graphene into PCL/gelatin matrix the tensile strength and Young modulus of nanofibrous mat considerably increased by 117 and 128% respectively. The electrical conductivity results demonstrated that nanofibrous mats own nearly 11 times higher conductivity than that of PCL/gelatin nanofibers when the graphene concentration reached the percolation threshold. Contact angle measurements confirmed that graphene-incorporated electrospun nanofibers were more hydrophilic than that of neat nanofibrous mats. Cellular toxicity results of electrospun nanofibers ascertained almost no toxicity to PC12 cells. The morphology of electrospun nanofibers was investigated by means of scanning electron microscopy (SEM). FTIR and DSC analysis revealed that there might be possible interactions between graphene and PCL/gelatin matrix. XRD analysis demonstrated that graphene-incorporated PCL/gelatin nanofibers exhibited higher crystallinity. The uniform dispersion of graphene nanosheets in nanofibrous mat was also verified through Raman spectroscopy.