Anticorrosion behavior of deposited nanostructured polythiophene on stainless steel, carbon steel, and aluminum in sea water
Abstract
In this study adherent films of polythiophene were deposited by electropolymerization of thyhiophene monomer ,onto stainless steel 316,carbon steel (C45), and aluminum (6061), the anticorrosion performance in artificial seawater (3.5% NaCl) solution were investigated at four temperatures, namely 20,30,40,50ᴼC using Tafel plots. The FTIR, XRD, TG, AFM, and SEM techniques, were used to evaluate the polythiophene deposited layer, they revealed nanofibers like structures with diameters around 40-50 nm , the thermal stability reach 300ᴼC.
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Introduction
The most interesting property of conducting polymers (CPs) is their high conductivity, which can be changed by simple oxidation or reduction. Conducting polymers usually have good corrosion stability when in contact with solution and in the dry state. In the recent years many papers have reported the use of CPs as materials for anti-corrosion coatings, applied on both ferrous and nonferrous metals, providing a potential cheap alternative to chromium and phosphate treatments and their pollution [1-4], For long time, polythiophene (PTh) has been widely used in environmentally and thermally stable conjugated polymer materials, Partly because of their good solubility, polythiophenes are among the better characterized conducting polymers have received considerable attention because of their remarkable electronic, magnetic and optical properties and their wide range of potential applications in many areas ,such as chemical and optical sensors , light-emitting diodes, displays , photovoltaic devices , molecular devices, DNA detection, polymer electronic interconnects, solar cells , transistors, and corrosion protection [5-7].
PTh can be synthesized using several techniques such as chemical and electrochemical methods [8-11]. The electrochemical method is used more often because it is environmental friendly and presents several advantages, this work focused on the electrochemical methods to apply layers of polythiophene through the electro-polymerization process on some metals and alloys namely carbon steel, stainless steel, and Aluminum to investigate the corrosion protection capability of this coating in saline water at different temperature by measuring corrosion rates and other factors including kinetics and thermodynamics parameters for the bare and coated specimens [12-16].
Conclusion
Specimens of SS316, AL, and CS were successfully coated with elctroplymerized polythiophene by potentiocyclic procedure using thiophene /acetonitrile /sodium perchlorate as electrolyte , the deposited layer have been well characterized using SEM, AFM, XRD, UV, FTIR, and TGA .They revealed compact highly ordered homogeneous fiber like nanostructure with particle size around 50nm over a large area of the surfaces. All coated samples showed good protection against corrosion in artificial seawater, the best was on SS316 and le lowest on CS.