Development of Modified Pencil Graphite Electrode Sensors by Using Polyaniline and Polypyrrole Based Poly(Acrylamide-Co-Amps) Hydrogels for the Detection of Methylene Blue

The present study is to synthesize hydrogels based on acrylamide, 2-acrylamido-2-methyl-propane sulfonic acid and copolymers of acrylamide/2-acrylamido-2-methyl-1-propane sulfonic acid with aniline and pyrrole to detect methylene blue dye. The copolymers samples composed of acrylamide with different amounts of 2-acrylamido-2-methylpropane sulfonic acid , aniline and pyrrole were synthesized using the cross linker N, N’-methylene bis acrylamide and the initiator potassium per sulfate by a free radical polymerization method. The cheap and disposable Pencil Graphite Electrodes using pencil leads, were developed by surface modification with polymeric hydrogels coating and were considered as working electrodes and sensors. Cyclic Voltammetry, Differential pulse Voltammettry and Square Wave Voltammetty was used to study the sensing property of the electrodes. The molecular structure of the hydrogel polymers was characterized by means of Fourier Transform Infrared Spectroscopy. The morphology of the resulting hydrogels polymers was studied by Scanning Electron Microscopy and X-ray Diffraction. The sensing properties of the polymeric hydrogels coated electrodes were tested in different concentration of Methylene Blue solution with variable dipping time of the electrodes. The Cyclic Voltammetry characterization proved that the copolymerization of aniline and pyrrole with the hydrogels and the hydrogels coated Pencil Graphite Electrodes as a sensor led to a considerable improvement in sensing behavior towards the methylene blue dye by producing significant current response.