Research On Fast Electropolymerization And Application Of Polyaniline Nanofibers

In the field of conducting polymer, polyaniline has become the research hotspotbecause of its low cost of raw materials, simple preparation method, goodconductivity, unique reversible doping machanism, with a wide range of applicationsin the metal anti-corrosion, supercapacitors, anti-static and electrochromic devices.In this paper, conductive polyaniline is synthesised rapidly by electrochemicalmethods, including cyclic voltammetry(CV), galvanostatic(GM) and potentiostaticmethod(PM), with carbon paper electrode as the substrate. Polyaniline nanofibershave a diameter of50~150nm, we also tested for their synthesis rate, morphology,conductivity and other physical and chemical properties. The results indicate that GMis the fastest method to synthesize polyaniline nanofibers, which is about25times ofthat when using conductive glass substrate. Polyaniline nanofibers synthesised by CVhave better uniformity and conductivity than that synthesised by GM or PM.Perchloric acid doped, sulfuric acid doped and hydrochloric acid dopedpolyaniline nanofibers (PANI-HClO4、PANI-H2SO4、PANI-HCl) are synthesised byCV respectively. X-ray diffraction results indicate that PANI-H2SO4have the highestdegree of crystallinity, the highest order of molecular chain orientation, maximumdoped degree, and the highest conductivity. Different acid-doped polyaniline/epoxyanti-corrosion coating are tested by open circuit potential(OCP), Tafel polarizationcurves and electrochemical impedance spectroscopy(EIS). The results show that thecorrosion resistance property of the coatings in descending order areEP/PANI-H2SO4> EP/PANI-HClO4> EP/PANI-HCl> EP/EB> EP.Perchloric acid doped polyaniline nanofibers in diameter of50~100nm aresynthesized on carbon paper electrode by CV, GM and PM, showing porous structureand some vertical growth. The electrochemical tests results indicate that, thedischarge capacitance of polyaniline nanofiber electrode material were578F/g,512F/g and445F/g at scan rate of20mV/s respectively, thus the polyaniline nanofiber electrode material synthesized by GM has the best capacitive performance. On theother hand, under the current density of3mA/cm2, discharge capacitance ofpolyaniline nanofiber electrode synthesized by GM is up to531F/g, higher than thePM and CV. Discharge/charge efficiency of polyaniline nanofiber electrodesynthesised by CV, GM and PM are all between90~100%. Impedance of polyanilinenanofibers electrode synthesised by GM is smaller than the PM and CV, with bettercharge transport performance, and better electrochemical capacitive performance.