Water soluble polyaniline coated electrode: A simple and nimble electrochemical approach for ascorbic acid detection

We report the design, synthesis, electrochemical stability and electrocatalytic applications of a new kind of water soluble polyaniline (PANI) composite. These water soluble PANI composites are extremely important in electrochemical sensor, semiconducting devices, light-emitting diodes, ultra-thin and flexible display devices, photoconductive sensors, and new fluorescent bio-probes. In the present work, we have prepared water soluble PANI using our designed and synthesized perylene disulphonic acid (PRSA) dopant. This PRSA dopant is a new and superior doping acid for synthesis of water soluble PANI. The PRSA/PANI composite prepared with it exhibits good electrochemical stability and superior electrocatalytic activity. It can sense ascorbic acid, a very important biomolecule, in neutral pH up to mM concentration level at the low electrochemical oxidation potential. Additionally, the modified electrode prepared from aqueous medium of PANI on ITO glass, is reusable and requires only a water rinsing and drying cycle in between measurements. PRSA/PANI composites also show a good semiconducting behavior and follow 1D-VRH (variable range hopping) electron transportation mechanism. The importance and novelty of this method are (i) synthesis of water soluble PANI by 'in-situ' polymerization method, which overcome the major and common problem of PANI processability in water; (ii) high performance electrocatalytic activity and reusability of PANI coated electrode. It also overcomes the electrochemical drawback of PANI synthesis, i.e. low yield, cost effective, limited processabilty etc.