Effects of Magnetic Field on the Phase Behaviors of Microemulsion System of Aniline Polymerization and Characterization of Electrochemical Properties of Polyaniline
|Keywords||Polyaniline Phase behaviors Magnetic field Carbon paper Electrochemistry|
As one of the most promising commercial conductive polymers, polyaniline (PANI) has advantages of ease of synthesis, unique doping-dedoping mechanism, excellent environmental stability and good electrochemical properties, which caused extensive public concerns. Currently, it has been widely used in basic materials, such as pH-sensors, rechargeable batteries, membranes and corrosion-protecting coating.Magmetic field (MF) affect has a marked impact on free radical polymerization. Therefore, the introduction of MF into the synthesis process of PANI can obviously improve doping degree, conductivity, crystallinity and thermal stability of the PANI. However, because of lower solubility and infusibility properties of the PANI synthesized by chemical polymerization, which seriously limits basic research of it’s electrochemical properties. Due to the characteristics of electrochemical inactivity, large surface, small pore size, high conductivity and stable chemical performance carbon paper, the electrochemical properties of the PANI can be effectively characterized by using the carbon paper loaded PANI as working electrode.The effects of MF and mass ratio of cosurfactant and surfactant (Km=m n-butanol /mSDBS) on the phase behavior, the conductivity behavior and the micro-emulsification of the microemulsion system of aniline polymerization was investigated by the pseudo-ternary phase diagram of sodium dodecyl benzene sulfonate (SDBS)/ n-butanol /aniline/H2O. The effects of preparation conditions such as the MF, the oxidant concentration and the polymerization time on the electrochemical properties of PANI were discussed by cyclic voltammogram and Tafel using the carbon paper loaded PANI as working electrode for the first time. The characterization results of the electrochemical properties of the products were proved by the analysis of the FT-IR spectra (FT-IR), X-ray diffraction (XRD), thermal analysis (TGA) and conductivity.The results showed that with the increase of alcohol content, the area of microemulsion region increased first and decreased afterwards, the area reached maximum on the condition of Km=1, and the area was increased by the MF. The characterization result of pseudo-ternary phase diagram was proved by the analysis of the solution conductivity with changes of water content in the presence of MF. The transmission electron microscopy (TEM) analysis result indicated that the particle-size of the PANI polymerized in the presence of MF was much smaller than that of PANI polymerized in the absence of MF. Conductivity, TGA and XRD analysis result indicated that the PANI synthesized in the presence of MF there is significant on the crystalline degree and the conductivity properties. FT-IR results indicated that the interaction force between molecules reduced, the delocalization of molecular chain increased, and the main characteristic peaks of the PANI prepared in the presence of MF had the trend of moving to low-frequency due to the orientation of MF, but the influence of magnetization on the basic structural units of PANI was not observed. The characterization results of the electrochemical properties of the PANI indicated that the electrochemical properties of the PANI synthesized by micro-emulsification polymerization can be real-time characterized efficiently by using the carbon paper loaded PANI as working electrode. The contrast analysis of the conductivity, XRD, TGA and FT-IR of the PANI also proved the effectiveness of the former method.