Ahmad Rouhollai - Department of Chemistry, Khajeh Nasir Toosi University of Technology, Tehran, Iran
Mohammad Hamed Barzegar Khaleghi - Department of Chemistry, Khajeh Nasir Toosi University of Technology, Tehran, Iran

Polyaniline (PANI) is a unique member of conducting polymers family due to its excellent mechanical and chemical properties [1]. These unique properties made PANI a suitable candidatefor different technological applications such as corrosion protection of metals [2].Despite its good characteristics PANI has the drawback of poor processability and solubility in commonly used organic solvents. This limits the application of PANI to its full potential [3]. In this work aneasily soluble PANI was formed via emulsion synthesis method. In this method different amounts of Dodecylbenzenesulfonic acid (DBSA) was used as emulsifying agent. In this procedureoptimized concentrations of aniline (0.5 M) and DBSA (0.1 M) were dissolved in 50 ml ofchloroform and vigorously stirred. 30 minute later 50 ml solution containing phosphoric acid (1 M) and ammonium persulfate (0.6 M) was slowly added to previous solution. Stirring wascontinued for 1 hour in room temperature. After that a green PANI containing DBSA was formedin the solution. The solvents were evaporated in an oven over night and obtained PANI-DBSA powder was thoroughly washed with deionized water. This green powder was first characterizedusing Energy-dispersive X-ray spectroscopy (edx) and X-ray diffraction spectroscopy (XRD) andthen used to formulate an anti corrosion coating based on epoxy resin matrix and xylene as a solvent for epoxy resin. Different carbon steel samples were prepared using this formulationincluded bare carbon steel electrodes, electrodes with epoxy coating and electrodes with differentpercent of PANI-DBSA in resin matrix. Corrosion protection performance of samples was investigated in a three electrode cell containing Ag/AgCl and platinum disk as reference andcounter electrode respectively in NaCl 3.5% as electrolyte solution. These test proved that PANIDBSA has high potential in corrosion protection of carbon steel. As it can be seen in Fig.1 Tafel polarization showed a 0.2 V potential change toward more noble potentials in case of 0.1 gr ofPANI-DBSA mixed with 3.6 gr of resin. Electrochemical impedance spectroscopy was also used to evaluate coatings performance. The results showed a relatively smooth surface with very high resistance is formed on carbon steel electrodes. In conclusion we prepared and examined a processable PANI derivate with good corrosion protection performance

Emulsion synthesis PANI-DBSA, Epoxy resin, Corrosion protection, Carbon steel