(93f) Preparation of Electrospun Nanocomposite Nanofibers of Polyaniline/Poly(methyl methacrylate) with Amino-Functionalized Graphene

Electrospinning technology has regained popularity in the last decade probably due in large part to the increased interest in nano-scale properties and technology. The electrospinning process is an efficient, relatively simple and low-cost technique to produce ultrafine fibers or fibrous structures of various polymers with diameters ranging from several nanometers to a few microns. Application of this process to electrically conductive polymers allows the production of conductive electrospun fiber mats that are very promising for many applications such as organic photovoltaics, scaffolds for tissue engineering and resistance-based sensors.

Gas sensors attract tremendous interest because of their widespread applications in industry, environmental monitoring, space exploration, biomedicine and pharmaceutics. Therefore, advances in sensor technology are constantly in demand, requiring improved sensors with faster response times, higher accuracies, increased sensitivities and other characteristics. Recently, 2D-graphene has attracted a lot of attention as a gas-sensing material since its discovery in 2004 due to its exceptional mechanical, thermal, chemical, electrical and optical properties. Moreover, it has high specific surface area that ensures every carbon atom as a surface atom and the electron transport through graphene may be highly sensitive to the adsorption/desorption of gas molecules. Graphene also has the ability to be dispersed in various polymer matrices thus creating a new class of polymer nanocomposites with new research dimensions in the fields of physics, chemistry, biotechnology and material science.

Among conducting polymers, polyaniline (PANI) remains the most popular due to its low cost, excellent optical and magnetic properties, high environmental stability and electrical properties that can be controlled by the oxidation and protonation state. However, it is relatively difficult to process compared to most other polymers. Polyaniline has a fairly rigid backbone due to its high aromaticity, and is commonly available only in relatively low molecular weight forms. Therefore, the elasticity of its solutions is insufficient for it to be electrospun directly into fibers. To circumvent this problem, it is possible to electrospun polyaniline by blending it with an easily electrospinnable polymer such as poly(methyl methacrylate) (PMMA). Moreover, polyaniline has successfully been demonstrated as an efficient gas sensor for monitoring organic and inorganic compounds.

In this work, we report the preparation of electrospun fiber mats of polyaniline doped with camphor-10-sulfonic acid, blended with poly(methyl methacrylate), and filled with amine-functionalized graphene using electrospinning for gas detection. The amine functionality in graphene will allow the high selectivity to carbon dioxide (CO₂). The combination of graphene with polyaniline using the electrospinning technique, as the conducting materials are good candidates for sensor matrices, with the advantages of low cost, easy preparation and ready modulation of sensing properties by varying their chemical structure. X-ray photoelectron spectroscopy, Fourier transforms infrared, Raman spectroscopy transmission electron microscopy and Scanning electron microscopy were used to characterize the amine-functionalized graphene and the morphology and properties of PANI/PMMA/AFG fiber mats, for detection of CO₂.