Polypyrrole Composite Coatings Research Articles

Au Nanoparticle–polypyrrole Composite Coatings with Enhanced Conductivity and Corrosion Resistance for Ti-Based Porous Transport Layer Anodes in Proton Exchange Membrane Water Electrolysis

Au Nanoparticle–polypyrrole Composite Coatings with Enhanced Conductivity and Corrosion Resistance for Ti-Based Porous Transport Layer Anodes in Proton Exchange Membrane Water Electrolysis

Electropolymerization of functionalized barium titanate reinforced polypyrrole composite coatings on nitinol alloy for biomedical applications

In the current study, the nitinol alloy (NiTi) was electrochemically coated with conductive polypyrrole (PPy) and polypyrrole/polydopamine functionalized barium titanate nanoparticles (PBT). The composite coatings were attained by adding different concentrations of PBT nanoparticles (1–10 wt%) to the electrochemical deposition bath. The results of transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dynamic laser scanning (DLS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) confirmed the successful development of a polydopamine (PDA) layer on the surface of barium titanate nanoparticles (BT NPs) and their incorporation into PPy matrix composite coatings. The optimum concentration of PBT was beneficial for coating adhesion strength due to PDA bonding with PPy and metallic substrate via the catechol moieties. Electrochemical examinations demonstrated that PPy/5PBT coating revealed excellent corrosion protection in the Ringer medium. The PBT particles also reduced the overall conductivity of the PPy coating by about tenfold and significantly improved the mineralization of the composite coatings by providing favorable sites for Ca ion adsorption and subsequent hydroxyapatite (HA) formation reactions. The results of osteoblast cell attachment revealed that PBT had a promising effect on the cellular behavior of the composite-coated samples.

Corrosion protection of carbon steels by electrochemically synthesized V-TiO2/polypyrrole composite coatings in 0.1 M HCl solution

Polypyrrole (PPy) composite coatings have been effectively synthesized in the presence of TiO2 and V-TiO2 nanoparticles on carbon steel by electrochemical method in aqueous oxalic acid solutions. These coatings were characterized by different surface analysis methods. TEM results confirmed that the size of V-TiO2 nanoparticles (11.91 ± 1.03 nm) was smaller than that of TiO2 nanoparticles (17.22 ± 2.84 nm), therefore increasing the interaction between PPy composite coatings and metal surface. The electrical conductivity measurement was carried out to examine the electrical properties of TiO2/PPy and V-TiO2/PPy composite coatings. Besides, the electrochemical behaviors of these coatings were also studied in 0.1 M HCl solution by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. Results showed that the V-TiO2/PPy composite coatings exhibited better anti-corrosion performance than TiO2/PPy composite coatings. The exceptional anti-corrosion performance of PPy composite coatings was associated with the synergistic effect of the increase in physical barrier, prevention of charge transport by TiO2 nanoparticles and the complex passive film on the metal surface.

Nanostructured Prussian Blue–polypyrrole composite coatings with electrochromic properties

The Prussian Blue–polypyrrole (PB/PPy) composite materials were obtained by a chemical redox process in a mixed solution of iron(III), hexacyanoferrate(III) and pyrrole with a nitrate supporting electrolyte. The morphology of the composites (as a sedimented powder or a film on the ITO-glass electrode surface) varied depending on the composition of synthetic solution.

Organic Coatings On Metal Surfaces ForCorrosion Protection

Polyaniline–polypyrrole composite coatings were formed on platinum and titanium substrates by galvanostatic electrochemical polymerisation. Electropolymerisation was done by varying the applied current and molar feed ratio of monomers. It was shown that the structure, yield and the morphology of the coatings were dependent on the feed ratio of monomers (aniline and pyrrole) and the applied current or potential. As the oxidation potential of aniline and pyrrole are very similar, we believe that simultaneous oxidation and codeposition of polyaniline and polypyrrole is possible by changing the applied potential. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of the resulting composites.

Characterization of polyaniline–polypyrrole composite coatings on low carbon steel: a XPS and infrared spectroscopy study

Polyaniline–polypyrrole composite coatings were electrochemically synthesized on low carbon steel under aqueous conditions. The coatings were characterized using X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy. The structure of the coatings was analyzed as a function of electrochemical deposition parameters (molar feed ratio of monomers and reaction time). The infrared spectroscopic analysis showed that a passive layer of iron(II) oxalate is formed at short reaction times. This inorganic layer undergoes dissolution thereby allowing the polymeric coatings to be formed on steel substrates. The infrared spectroscopy also showed significant changes in the chemical structure of the composite coatings when compared with the homopolymeric coatings. X-ray photoelectron spectroscopy was used to study the chemical composition of the coatings and also the amount of dopants (oxalate ions) incorporated into the polymeric coatings.

A one-step electrochemical synthesis of polyaniline–polypyrrole composite coatings on carbon fibers

Polyaniline–polypyrrole composite coatings were formed on carbon fibers by potentiostatic electrochemical polymerization. Electropolymerization was done by varying the applied potential and molar feed ratio of monomers. The dual nature of the composite coatings was deduced from the current–time ( I– t) curves traced during polymerization. I– t curves were also used to predict the mechanism of the formation of composite coatings. UV–vis absorption spectroscopy was used to study the electronic structure of the composite coatings.

Electrochemical deposition of polyaniline–polypyrrole composite coatings on aluminum

AbstractThe electrodeposition of polyaniline–polypyrrole composite coatings on aluminum was successfully performed by using cyclic voltammetry. Oxalic acid was used as the electrolyte. Electrodeposition was carried out at a scan rate of 20 mV/s by varying the number of cycles. An anodic peak current at around −0.1 V versus saturated calomel electrode (SCE) was observed in the cyclic voltammograms. This peak is due to the oxidation and adsorption of hydrogen. The cyclic voltammograms also show another anodic peak current at around 1.0 V versus SCE, which is the characteristic peak of the polyaniline–polypyrrole composite. The behavior of this peak with respect to the number of cycles is discussed in detail. A corresponding cathodic peak current at around −0.7 V versus SCE was also observed in the cyclic voltammograms. The infrared spectra of the composite coatings revealed the infrared peaks of both polypyrrole and polyaniline. The scanning electron micrographs of the coatings indicate a morphology completely different from its homopolymers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1970–1977, 2002

Corrosion Protection Properties of Polyaniline–polypyrrole Composite Coatings on Al 2024

Polyaniline–polypyrrole composite coatings were deposited onto Al 2024 using an electrochemical process. The effect of incorporating inorganic fillers such as clay and yttria stabilised zirconia on the corrosion performance of the composite coating was studied. The coatings were analysed using infrared spectroscopy and scanning electron microscopy. The electrodeposition parameters such as feed monomer ratio, applied current density, and reaction time were systematically varied. Results showed that the composite coatings improved the corrosion resistance of the substrate.

Development of polyaniline–polypyrrole composite coatings on steel by aqueous electrochemical process

Polyaniline–polypyrrole composite coatings were formed on low carbon steel using oxalic acid as electrolyte by a potentiostatic method under aqueous conditions. A passive layer of iron (II) oxalate is deposited on the steel surface prior to the formation of composite coatings. The electrochemical process shows three distinct regimes — formation of passive layer, dissolution of passive layer and formation of polymeric composite coatings. These three regimes have been studied in depth using spectroscopic techniques and electron microscopy. Quantitative analysis of the current–time transient ( I– t) curves show that the nucleation and growth of the passive layer occur by three-dimensional (3D) instantaneous nucleation and that of the composite coatings occur by 3D progressive nucleation. It has also been shown that the morphology of the composite coatings depends upon the electrochemical deposition parameters.

Electrochemical synthesis of polyaniline–polypyrrole composite coatings on carbon fibres in aqueous toluene sulphonate solution

Polyaniline and polypyrrole were codeposited electrochemically on carbon fibres under potentiostatic conditions. Electropolymerisation was carried out by varying the applied potential and the feed ratio of monomers. The progress of electropolymerisation was monitored by weight gain analysis and infrared spectroscopy. The thermal stability of the coatings was determined by using thermogravimetric analysis and differential scanning calorimetry. Characteristic behaviour of polyaniline and polypyrrole can be deduced from the weight gain plots. Formation of polyaniline–polypyrrole composite coatings was further confirmed by the presence of characteristic peaks for polyaniline and polypyrrole in the infrared spectra. Thermal analysis also revealed the behaviour of the composite. Composite coatings composed of polyaniline and polypyrrole were formed at applied potentials of <1·0 V. Polypyrrole is preferentially formed at 1·5 V. Scanning electron micrographs were also used to illustrate the composite behaviour.

Fourier transform infrared spectroscopy studies of polypyrrole composite coatings

Pyrrole monomer was dispersed in polyvinyl alcohol (PVA) and polyvinyl acetate (PVAc) solutions, which were previously mixed with an iron chloride solution. The resulting mixtures were coated on substrates, and as the solution solvents were evaporated pyrrole was polymerized in the composite coatings. The very low percolation threshold values and the continuous percolation phenomena of the electrical conductivity of these coatings suggest a chain structure of the conductive PPy in the composites and a good miscibility between the conductive phase and the insulator hosts as well. FT-IR studies of the coatings suggest molecular interactions between the functional groups of the polymer matrices and PPy through the iron salt molecules, which could be the reasons for the good miscibility between the semiconductor and insulator components of the composite coatings.