Research and fabrication of conducting polyaniline nanoparticles by electrochemical and chemical methods

Laboratory for Ultrastructure Research, Ha mamatsu University School of Medicine,1-20-1 Handayama, Hamamatsu-City, 431-3192 JapanABSTRACT:Conducting polyaniline (PANi) and their composite nanoparticles were synthesizedby both electrochemical and chemical methods. In electrochemical method, PANi andits composite were electro-synthesized in acidic medium (sulphuric acid and oxalicacid) on iron by cyclic voltammetry technique. In chemical method, PANi and itscomposite were polymerised by a self-assembly method using ammoniumperoxydisulfate as an oxydant under supersonic stirring in aqueous medium.The obtained PANi product was characterised by Infra-Red and Ramanspectroscopies. The nanostructure of PANi was examined by using Scanning andTransmission Electron Microscopes.The results obtained in electrochemical method shown that PAni nanoparticlescould be archived by transformation from its traditional fibrous structure using a bulkydopant as organic acid (oxalic acid), an oxydable subtract (iron) and an additional lesselectro-active monomer (diamino-naphthalene : DAN). The nano-size of PANi particlessynthetized in chemical method could be controlled by using supersonic stirringconditions and participation of ad ditional metallic oxide particles (ZnO).I. INTRODUCTIONConducting polymer is new material, which combines the electronic and opticalproperties of metals and semiconductors and the mechanical properties and easy ofprocessing of polymers. Polyaniline (PANi) is regarded to be a most favored conductingpolymer for practical applications due to its excellent properties (special dopingmechanism, good environmental stability, high conductivity, low cost...), and potentialapplications (in batteries [1], electrochromic display device [2], bio and chemicalsensors [3,4], micro- and nano-electronic device [5], corrosion prevention [6], RF andmicrowave absorber [7] and antistatic materials [8]). Nevertheless, its commercialapplication was limited due to its insolubility in common solvent [9]. In order toimprove its solubility, HCl dopant has been replaced by various bulky dopants asbenzene-sulfonic acid, sulfosalicyclic, camphor sulfonic acid and dodecylbenzensulfonic acid, that expected to enlarge the distance of PANi molecules for permitting of