Studies Of Solid-state Synthesis Of Polyaniline And Its Derivatives

Polyaniline is one of the most interesting conducting polymers due to its environmental stability, ease in preparation, exciting electrochemical, optical and electrical properties and possible applications in rechargeable batteries, microelectronics devices, biosensors, electrochromic displays and chemical sensors. In this thesis, polyaniline salts and its derivatives were prepared by a novel solid-state polymerization method with the organic sulfonic acids (?-naphthalenesulfonic acid, camphorsulfonic acid, p-toluine sulfonic acid), heteropolyacids (H7PW12O42, H3PMo12O40) and inorganic acids (HCl, H2SO4 and H3PO4) as doping agents, respectively. Relative polyaniline salts were characterized by FTIR spectroscopy, X-ray diffraction, UV-vis spectroscopy , SEM and TEM. The electrical conductivities of these polymers were measured. The main results are summerized as follows: 1. The particles of polyaniline doped with ?-naphthalenesulfonic acid were sphericalin shape, and the average size was ~30～50 nm which obtained by a solid-state reactionmethod. The measured electrical conductivity of polyaniline nanoparticles was 17 S/cm.Polyaniline naoparticles showed good electrochemical properties by using powdermicroelectrode technique. 2. The polyaniline doped with camphorsulfonic acid prepared by a solid-state reactionmethod displayed higher crystallinity , less structural defects and spherical microstructure ,high inherent viscosity (1.61 dL/ g) and better electrochemical stability. 3.Poly (o-toluidine) (POT) salts doped with organic sulfonic acids (e.g., NSA, CSA andp-TSA) were directly synthesized by using this solid-state polymerization method.Spectroscopic studies showed here is the highest ratio of the relative intensities of the quinoidto benzenoid unit in NSA doped POT, where as the conducting emeraldine salt phase isformed predominantly in p-TSA doped POT and the doping level of POT-CSA is the lowestamong the POT salts. More crystalline POT salt was obtained by doping with p-TSAcomparing with the other organic acids, and p-TSA was found to be more suitable as aprotonic acid media to obtain a POT with high conductivity in this solid state polymerizationmethod. 4. Polyaniline doped with H7PW12O42 prepared by solid-state reaction synthetic methodnot only has good order and crystallinity , but also displays the good electrochemicalproperties.The one which prepared in the presence of small amount of acetonitrile has bettercrystallinity, smaller particles size and better electrochemical properties than that ofprepared in the small amount of water. 5.Polyaniline doped with H3PMo12O40 prepared by solid-state reaction synthetic methodalso has good order and crystallinity compared with that synthesized in traditional liquidphase polymerization method. The polyaniline doped with H3PMo12O40 prepared bysolid-state reaction displayed better electrocatalytic activity on the oxidation of ascorbic acid. 6. Polyaniline doped with inorganic acids (e.g., HCl, H2SO4and H3PO4) synthesized bysolid-state polymerization showed here is the highest ratio of the relative intensities of thequinoid to benzenoid unit in H3PO4 doped PANi and leucoemeraldine phase is formedpredominantly in PANi salts.These results were further supported by conductivitymeasurements and cyclic voltammetry. More crystalline PANi salt was obtained by dopingwith HCl comparing with other inorganic acids in this method. Among these inorganic acids,HCl was found to be more suitable as a protonic acid media in order to attain a PANi withhigh conductivity in this solid state polymerization . 7.Polyaniline doped with hydrochloride acid has been firstly prepared using solid-statereaction synthesis method at room temperature and (0℃). Polyaniline particles werecharacterized by FT-IR, SEM, XRD and cyclic voltammogram. Compared with thepolyaniline prepared by using liquid phase method at room temperature, the polyanilinedoped with hydrochloride acid synthesi...