The Preparation And Stabilization Of Conductive Polyaniline Films

Polyaniline ( PAn) have potential applications in technology: Such as light-emitting diodes (LED), sensors, rechargeable batteries, photovoltaic cell, electromagnetic interference shielding and metal anti-corrosion because of their variable structure, varied electronic properties through doping and lightweight. The problems for the applications of polyaniline are mainly focused on the processibiling and stability of polyaniline and functional polyaniline.Based on previous works, the emulsion polymerization of aniline in water?xylene system with sulfosalicylic acid as dopant was studied. The conductivity of polyaniline was 4.2 S-cm"1. The differences between the polyaniline prepared by emulsion polymerization and hydrochloric acid solution polymerization were evaluated. The solubility and thermal stability of polyaniline doped by sulfosalicylic acid was better than that by hydrochloric acid. In comparison to oil-phase emulsion polymerization reported in the articles, the water-phase emulsion polymerization in this research work is easier to operate in synthesis and does not need separating solvent from polymer.Conductive polymer composite film of polyaniline /poly (vinyl alcohol) (PAn /PVA) was synthesized with an in-situ polymerization. The conductivity of the composite film was determinated to be 4.36 S-cm'1. Thermal stabilities of this composite film and pure PAn were investigated by baking polymers in air atmosphere at 200 *C. The results showed that PAn /PVA has a higher stabilify than pure PAn.A series of polyaniline film doped by sulfosalicylic acid were prepared by using the different methods. The conductivity, thermal stability and microstructure are measured. The results showed that the compact film can much resist heat and has higher conductivity than the loose one.An epoxy anti-corrosive paint was prepared with polyaniline doped sulfosalicylicIIIABSTRACTacid as anti-corrosive agent. The phase texture of fracture surface on the coating was observed by SEM. The results showed that granulated polyaniline formed crossing network in the coating, so the coating is well conductible. Through the immersion experiments in 15%NaOH,10?iH2SO4 and 10%NaCl solutions, it was found that this paint had high anti-corrosion performance. When there were scratch marks on the surface, this paint still had anti-corrosive effect to steel because of PAn's variable structure and electronic properties.