Ahmad Abdolahi

Synthesis of Uniform Polyaniline Nanofibers through Interfacial Polymerization

The present paper aims to study the preparation of polyaniline nanofibers through simple interfacial polymerization. Ammonium persulfate, hydrochloric acid and chloroform were used as oxidant, dopant and organic solvent respectively. Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction and Fourier Transform Infrared Spectroscopy (FTIR) techniques were used to analyze the product. FESEM results show that polyaniline has nano-fiber morphology. XRD results show the crystalline properties of polyaniline nanofiber, and FTIR results confirmed the formation of polyaniline in different monomer/oxidant molar ratios. This study provides a better understanding on the synthesis of uniform polyaniline nanofibers through interfacial polymerization.

Improvement of thermally grown oxide layer in thermal barrier coating systems with nano alumina as third layer

Abstract A thermally grown oxide (TGO) layer is formed at the interface of bond coat/top coat. The TGO growth during thermal exposure in air plays an important role in the spallation of the ceramic layer from the bond coat. High temperature oxidation resistance of four types of atmospheric plasma sprayed TBCs was investigated. These coatings were oxidized at 1000 °C for 24, 48 and 120 h in a normal electric furnace under air atmosphere. Microstructural characterization showed that the growth of the TGO layer in nano NiCrAlY/YSZ/nano Al2O3 coating is much lower than in other coatings. Moreover, EDS and XRD analyses revealed the formation of Ni(Cr,Al)2O4 mixed oxides (as spinel) and NiO onto the Al2O3 (TGO) layer. The formation of detrimental mixed oxides (spinels) on the Al2O3(TGO) layer of nano NiCrAlY/YSZ/nano Al2O3 coating is much lower compared to that of other coatings after 120 h of high temperature oxidation at 1000 °C.

Influence of Pseudomonas aeruginosa bacteria on corrosion resistance of 304 stainless steel

Abstract Microbiologically influenced corrosion (MIC) is a corrosion phenomenon that is destructive to many industries. This research aims to investigate on the MIC behaviour of a 304 stainless steel (SS) substrate in a nutrient rich simulated seawater inoculated with Pseudomonas aeruginosa bacteria. Atomic force microscopy, scanning electron microscopy and energy dispersive spectroscopy (EDS) techniques were used to analyse MIC behaviour of 304 SS. Atomic force microscopy was used to observe the degree of pitting corrosion on 304 SS due to the presence of P. aeruginosa bacteria. Scanning electron microscopy and EDS were used to analyse the biofilm layer formed on 304 SS. The considerable feature was the severe pitting corrosion of 304 SS due to presence of P. aeruginosa in biofilm state.

Microbially influenced corrosion of steels by Pseudomonas aeruginosa

Abstract Microbially influenced corrosion (MIC) is a destructive type of corrosion that is initiated, facilitated, or accelerated by the presence and metabolic activity of bacteria. MIC of steels is a great issue in many industries such as marine, freshwater systems, and gas/oil pipelines. Pseudomonas aeruginosa is one of the aerobic slime-forming bacteria that are ubiquitous in marine environment that corrode steel structures. This article aims to provide a review on MIC of steels caused by bacteria, mostly in the case of P. aeruginosa. The mechanisms of MIC will be discussed based on bacteria-metal reactions and emphasize the role of P. aeruginosa on corrosion of steels.

Application of Environmentally-Friendly Coatings Toward Inhibiting the Microbially Influenced Corrosion (MIC) of Steel: A Review

Microbially influenced corrosion (MIC) is an electrochemical type of corrosion that is initiated, facilitated, or accelerated by bacteria and biofilms on the metal substrate. To inhibit MIC, coating methods have been widely used because of their effectiveness, ease of application, and low cost. Coatings used for MIC inhibition should have antibacterial and anticorrosive properties. Conventional coatings for MIC inhibition are based on heavy metals such as tin, copper, and zinc; these coatings are toxic to the environment. Recently, environmentally-friendly coatings were developed to inhibit MIC. Among these new coatings, studies have focused on conductive polymers, which have both antibacterial and anticorrosive properties. These conductive polymers have biocidal activity due to the positively charged nitro-groups in their chains. Moreover, due to their good redox properties, these polymers can passivate steel, imparting anticorrosive properties. The biocidal and anticorrosive properties of conductive polymers make them appropriate coatings for MIC inhibition. This study reviews the antibacterial and anticorrosive properties of different types of polymer coating concentrates in environmentally-friendly conductive polymers for inhibition of MIC of steels.

Synthesis and characterization of high-quality polyaniline nanofibres

This article aims to study the synthesis of high-quality polyaniline (PANI) nanofibres through simple interfacial polymerization method in the presence of different acids. Ammonium persulphate, chloroform and different acids were used as oxidant, organic solvent and dopant, respectively. Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were used to characterize the PANI nanofibres. FESEM results show different morphologies of PANI particles were produced from the various acid mixtures. FT-IR and XRD results confirmed the formation of PANI particles. XRD results show that PANI nanofibre is partially in crystalline nature.

Localised corrosion of mild steel in presence of Pseudomonas aeruginosa biofilm

Microbially influenced corrosion (MIC) is a destructive type of corrosion, which is initiated, facilitated or accelerated by the presence of bacteria. The objective of this study is to determine the MIC behaviour of mild steel exposed to Pseudomonas aeruginosa inoculated nutrient rich simulated sea water medium. The formation of the biofilm layer, corrosion products and pitting areas on the steel substrate are characterised by field emission scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy and atomic force microscopy. The overall results showed the aggressive role of P. aeruginosa biofilm in inducing the corrosion process and generating significant pits on steel. This study may provide a new understanding of the MIC behaviour of steel caused by bacterial colonisation and biofilm formation.

Synthesis and Characterization of Polyaniline-Polypyrrole Composite

The current paper aims to study on synthesis of polyaniline (PANI)-polypyrrole (PPY) composite through simple interfacial polymerization method using chloroform as organic solvent, ammonium persulphate as an oxidant agent and sulphuric acid as a dopant. The composite was characterized by using Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and four pint probe methods. FESEM results showed the formation of fibrous PANI-PPY composite. FTIR and XRD results confirmed the successful formation of PANI-PPY composite. Four-point probe results showed the low electrical conductivity of the product. This study gives the better understanding on synthesis and characterization of the PANI-PPY through simple interfacial polymerization method.

Facile synthesis of polyaniline-silver composites through interfacial polymerization

In this paper, the simple synthesis of polyaniline/silver composites through interfacial polymer method was studied. Polyaniline-silver composites were produced at room temperature by using ammonium persulphate as an oxidant agent in presence of silver nitrate (AgNO3). Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques were used to characterize the synthesized product. FESEM results showed the core shell shape of composites that the layer of polyaniline covered the silver particles. XRD results showed the high crystalline behaviour of the polyaniline/silver composites due to presence of silver. FTIR results also showed the successfully synthesis of the composite. This paper aims to study on synthesis and characterization of polyaniline-silver composites.

Characterizations of Zeolite, Polyaniline and Zeolite/Polyaniline as Antifouling Materials for Marine Applications

In this paper, the basic synthesis of encapsulated zeolite, polyaniline and zeolite/polyaniline composite as self-healing core materials for antifouling coatings was studied through interfacial polymerization. All materials were synthesized by using ammonium persulphate as an oxidant agent. Field Emission Scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) techniques were used to characterize the synthesized materials. This paper aims to study on synthesis and characterization of zeolite, polyaniline and zeolite/polyaniline composite as self-healing core materials for antifouling applications. FESEM revealed that a smooth and homogeneous microstructure of materials. XRD results showed the high crystalline nature of all materials. FTIR showed the successful synthesis of the three materials. Finally, DSC results revealed appreciable Thermal properties of the developed materials.