Effect Of A Magnetic Field On Structure,Doping Characteristics And Properties Of Polyaniline Doped With Multiple Sulfonic Acids

Polyaniline (PANI),an inherently conducting polyme(rICP)is unique among the family of those conducting polymers and has been regarded as one of the more promising conductive polymer materials for commercial applications because of its low cost, ease of preparation, unique chemical and physical properties controlled by the oxidation and protonation state, as well as excellent environmental stability. However, major problems related to its successful utilization lies in its poor conductivity and processibility due to its insoluble nature in common organic solvents. Although much progress such as the approach of emulsion polymerization method and use of functional dopant has been made to improve both these aspects, yet, the problems is not solve completely.It is well known that all materials respond to a magnetic field. The response may be repulsion (negative magnetic susceptibility) representing diamagnetism, or attraction (positive magnetic susceptibility) representing para- and ferromagnetism. The most important magnetic field effects on purely diamagnetic molecules are magnetic orientation and concentration. PANI is diamagnetic molecules, the existence of magnetic field can greatly increase ordered and regularly of PANI chain, and improve the conductivity, and solubility of PANI.Polymerization processes that are directly dependent on the radicals and whose presence determines the subsequent evolution of reactions,will be consequently influenced by the existence of an external continuous magnetic field and can exhibit magnetokinetic effects. The polymerization process of aniline is radical polymerization, which will be influenced by the existence of an external magnetic field and can exhibit magnetokinetic effects.PANI doped with multiple sulfonic acids system of dodecylbenzenesulfonic acid (DBSA) and sulfosalicylic acid (SSA) are synthesized by emulsion polymerization under the presence and the absence of a constant (0.8T) magnetic field. The structure and properties of the PANI are characterized by X-ray diffraction (XRD), Thermogravimetric analysis (TGA), FT-IR spectroscopy (FT-IR) and four probe digital multimeter,and the apparent behavior of doping kinetics of the PANI are discussed. The results show that the molecular chain of PANI synthesized under the presence of the magnetic field is much ordering than the PANI synthesized under the absence of the magnetic field, the conductivity, the molecular weight, the solubility, the doping degree, the crystallinity and the thermal stability of the PANI synthesized under the presence of the magnetic field are improved than the corresponding PANI synthesized under the absence of the magnetic field. The magnetic field can not only enhance the conductivity but also reduce the doping time, the dosage of the dopant and the oxidizing agent that the conductivity reaches to the maximum.The apparent behavior of doping kinetics of the PANI result shows that the magnetic field have effect of orientation during process of synthesizing the PANI, which result in the PANI chain more stretching that make for the dopant more easy doped onto the PANI backbone so as to the polymerization rate,the doping rate,the yield,doping degree and the solubility of the PANI has been obviously improved in the magnetic field.