Synthesis And Nature Of Conducting Polymers Such As Poly Phenol

The electrochemical synthesis and properties of polyphenol and poly(azure A) and "green" synthesis of polyaniline were mainly studied in this graduation thesis.1. The electrochemical preparation of polyphenol with conductibilityPolyphenol film deposited on platinum foil can continuously grow with time during the electrolysis of a phenol solution consisting of 0.1 mol-dm-3 phenol, 3 mol.dm-3 NaOH and 0.5 mol.dm-3 Na2SO4 which has been proved by the methods of sweep potential, constant potential and constant current, and visible spectra during the electrolysis of phenol. A polyphenol film with thickness of 0.11 mm was obtained by the electrolysis of phenol at a constant potential of 0.70 V (versus Ag/AgCl with saturated KC1 solution). Polyphenol film is an inactive and stable in 2 mol.dm-3 H2SO4 solution, neutral solution and 3 moldm"3 NaOH solution and at the potential range between -0.95 and 1.35 V. The usable potential range is dependent on the pH value. Polyphenol has an ESR signal with a g factor of 2.0049. The conductivity of polyphenol is 1.2×104 S .cm-1. In the solution of polyphenol dissolved in DMSO, the mobility of polyphenol anions is 8 × 10-9 mV.V-1 at 20℃. The FTIR spectrum of polyphenol is presented in this chapter.2. The electrochemical polymerization of azure A and the properties of poly(azure A)The electrochemical polymerization of azure A has been carried out using repeatedpotential cycling. The scan potential is set between -0.2 and 1.3 V (versus Ag/AgCl with saturated KC1 solution). The electrolytic solution consisted of 5 mmol-dm"3 azure A and 0.5 mol.dm-3 Na2SO4 with pH 6.0. The temperature for polymerization was controlled at 50癈. An anodic peak and a cathodic peak appear at 0.38 and 0.23 V, respectively, on the cyclic voltammogram of poly(azure A) in 0.5 moldm-3 Na2SO4 solution of pH 1.0. Their peak potentials shift towards the negative direction as pH value increases from 1.0 to 4.0. Poly(azure A) has a good electrochemical activity and stability in the aqueous solution at the above pH range. The UV-Visible spectrum and FTIR spectrum of poly(azure A) are different from those of azure A. The FTIR spectrum of poly(azure A) indicates that no anions were doped into the oxidation form ofpoly(azure A).3. "Green" synthesis of poly anilinePolyaniline was synthesized chemically with ferric sulfate as oxidant. The in situ visible spectra of the polymerization of aniline in different concentrations of sulfuric acid show that a peak at 720 nm first formed and its absorbance increases with reaction time, and then another peak at 520 nm gradually formed. Polyaniline with the peak at 720 nm has a small solubility in water, depending on the concentration of sulfuric acid used for the polymerization of aniline. However, polyaniline with the peak at 520 nm can completely dissolve in water. Water-soluble polyanilines with intense color will cause environmental pollution. The IR spectra and cyclic voltammograms of polyaniline are affected by the concentrations of sulfuric acid used for the electrochemical polymerization of aniline. The optimum conditions for "green" synthesis of polyaniline are that the solution consisted of 0.2 mol.dm-3 aniline, 0.1 mol.dm-3 ferric sulfate and 0.2 mol.dm-3 sulfuric acid and the reaction temperature was controlled below 15℃.