Preparation And Kinetic Of Polyaniline Film In A Constant Magnetic Field

Polyaniline(PANI) is one of the most commercially valuable conducting polymers duo to its low cost, ease of synthesis, excellent environmental stability. PANI composite have a wide rang of potential applications in electrochemical, Anti-corrosion, battery materials because of its exciting mechanical, optical and electrochemical properties.PANI is diamagnetic molecules, the presence of the magnetic field can greatly increase ordered and regularly of PANI chain. In the electrochemical system, a Lorentzian force will act on the valence electrons when magnetic field couples with an electric field, this force leads to migration of ions, generates solution streaming; reduces the thickness of the boundary layer and increases the mass transportation rate. The magnetic field not only can influence on the autocatalysis process of aniline, but also can influence on the morphology and properties of the PANI films.The magnetic field can influence on the chemical reaction containing radicals. Currently, it has attracted much that the An polymerized in the presence of magneticfield and the effects of magnetic field on the properties of PANI were discussed. The electrochemical properties of PANI film which prepared by the electrochemical method and the effect of composite oxidant (FeCl3/APS) on the kinetics behaviors of PANI films formation by emulsion polymerization in the presence of the magnetic field have been studied in this dissertation. The results show that:(1)The conditions of PANI film prepared by the electrochemical method were optimized by the electrochemistry testing: excitation voltage was 1.40¹.45V, excitation cycles was two cycles; working voltage was -0.2V⁰.9V; the number of cycles was forty cycles in the presence of magnetic field perpendicular to the electric field. The films of PANI prepared in these conditions showed better conductivity, redox reversibility, cycle stability and corrosion properity.(2) PANI polymerized in emulsion using dodecylbenzene sulfonic acid (DBSA) as dopant and emulsifier, ferric chloride and ammonium persulfate as composite oxidant in the presence and absence of a constant magnetic field (0.4 T) exhibited the same reaction order: first order with respect to composite oxidant, half-order to An and half-order to dodecylbenzene sulfonic acid (DBSA). And the polymerization conditions of PANI were optimized tentatively by the cyclic voltammertry testing, The results showed that the peak currents and conductivity of PANI were the largest in the conditions: the magnetic field intensity was 0.4T, the molar ratio of FeCl₃/APS was 2:1, the concentration of composite oxidant was 0.18 mol/L, the concentration of aniline and DBSA were 0.08 mol/L and 0.05 mol/L.