(413f) Coaxial Electrospun Nanofibers of Polyaniline/Poly(methyl methacrylate) Filled with Graphene

Electrospinning is a simple method to produce nanofibers mats with diameters in the nanometer scale. The technique is based on the application of an electric field on a polymer solution, and it is considered one of the most efficient techniques to fabricate high performance nanofibers mats, with distinct advantages such as very high surface area to volume ratio and porosity. Polyaniline (PANi) is one of the most studied intrinsically conductive polymer, mainly due to its ease of synthesis and interesting doping mechanism. It is however daunting to process PANi compared to most other polymers. As it is common among intrinsically conductive polymers, PANi has a fairly rigid backbone because of its high aromaticity. Thus, electrospinnability of PANi is limited due its insufficient solution viscosity and rigid chemical structure. One approach to make PANi electrospinnable is by its blending with materials that may facilitate its electrospinnability such as easily electrospinnable copolymers (e.g poly(ethylene oxide) and poly(lactic acid)), as previously reported. However, the presence of an insulating copolymer decreases the fibers conductivity due to dilution of the conducting component. The coaxial electrospinning method provides an alternative and effective way of fabricating neat PANi nanofibers. Coaxial electrospinning is an innovative electrospinning method that facilitates the fabrication of unspinable polymer nanofibers with unique core−shell structures. In this technique, two dissimilar solutions are spun simultaneously through a spinneret composed of two coaxial capillaries to produce core−shell structured nanofibers with unspinable polymer at the core section. Recently, graphene, a single-atom-thick two-dimensional sheet of sp²-hybrized carbon atoms arranged in a honeycomb crystal structure, has attracted a lot of research interest and has been considered as a rising-star carbon material. Graphene has been intensively researched because of its remarkable properties such as high electrical and thermal conductivities, high mechanical strength and large surface area. Given its excellent electrical conductivity and electron mobility at room temperature, a highly conductive graphene-based polymer nanocomposite may be obtained. In this work, we report the preparation of neat polyaniline fibers filled with highly dispersed graphene sheets. The coaxial electrospinning process was used to produce core-shell structured fibers of a poly(methyl methacrylate) shell and a polyaniline core embedded with highly dispersed graphene nanosheets. The insulating shell was selectively removed by solvent etching. SEM, TEM, XPS and electrical conductivity measurements were employed to characterize these nanofibers.