Polypyrrole coatings for corrosion protection of Al alloy2024: influence of electrodeposition methods,solvents, and ZnO nanoparticle concentrations

Since ZnO nanoparticles increase the electrical conductivity of the polypyrrole (PPy) coatings, an investigation was carried out to evaluate the effect of ZnO nanoparticles loading on the corrosion protection performance of PPy coatings on AA2024 Al alloy in 3.5% NaCl solution. At first, some measurements were carried out to find the best experimental conditions containing the electrodeposition method, electrosynthesis solvent composition, and ZnO nanoparticles’ concentration for preparing the optimum PPy coating on Al alloy2024. Three different methods of electrodeposition, namely: cyclic voltammetry, galvanostatic, and potentiostatic techniques were analyzed. The anti-corrosion performance of the PPy coatings was evaluated by electrochemical impedance spectroscopy and Tafel polarization methods. The PPy prepared by potentiostatic method exhibited the best performance against corrosion of Al alloy2024 in 3.5% NaCl solution. Then, different mixtures of H₂O/ethanol were tested as electrosynthesis solvents for preparation of PPy coatings on the alloy by optimized electrodeposition mode (i.e., potentiostatic). In evaluation of the prepared coatings, the pure water was introduced as the optimum solvent in electrodeposition of PPy. The investigation of different ZnO nanoparticles’ concentrations proved that the PPy coating containing 0.025% ZnO nanoparticles was the optimum coating against the corrosion of Al alloy in NaCl solution. Finally, the long-term evaluation of the corrosion protection performance of the coatings revealed that the optimum coating provided suitable protection against corrosion up to 14 days after immersion.

     

Development of epoxy/rice straw-based cellulose nanowhiskers composite smart coating immobilized with rare-earth doped aluminate: Photoluminescence and anticorrosion properties for sustainability

Novel epoxy resin (E)/CNW nanocomposite coatings were developed with different total contents of rare-earth doped aluminate nanoparticles (REA NPs). The produced epoxy-cellulose nanowhiskers-rare earth doped aluminate nanoparticles (E-CNW-REA) coatings were applied onto mild steel. The epoxy/CNW nanocomposite coatings were characterized by X-ray fluorescence analysis (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXA), transmission electron microscope (TEM) and infrared spectra (FT-IR). Both colorimetric properties and transparency of the nanocomposite coatings were proved by exploring UV–Vis absorption spectroscopy and CIE Lab parameters. The hardness and superhydrophobic properties were also explored. The photoluminescent transparent coatings showed an excitation at 365 nm, and a bright green emission wavelength at 517 nm under UV light. The corrosion protection performance of the coated mild steel samples soaked in an aqueous solution of sodium chloride (3.5%) was investigated using electrochemical impedance spectroscopy (EIS). The coatings with CNW were found to have anti-corrosion properties. Moreover, the nanocomposite coating with CNW (1 w%) was monitored to exhibit the most pronounced long-persistent photoluminescence for 60 min in the dark. The photoluminescent coatings exhibited highly durable long-lasting phosphorescence. Thus, the current strategy can be considered as a simple promising technology for industrial production of anti-corrosive, superhydrophobic and long-persistent phosphorescent.     

Poly(styrene-alt-maleic anhydride) ionic salt functionalized reduced graphene oxide doped with rare earth ions for anti-corrosion performance enhancement

A novel organic–inorganic nanocomposite material of rare earth ions/ poly(styrene-alt-maleic anhydride) ionic salt/ reduced graphene oxide ( Re³⁺/SMA-Is/rGO) was prepared successfully. Poly(styrene-alt-maleic anhydride) ionic salt functionalized reduced graphene oxide (SMA-Is/rGO) was processed with two methods of π–π conjugation and ionization; rare earth ions (Re³⁺ = La³⁺, Ce³⁺ Pr³⁺) was doped on the surface of rGO by physical mixing. SMA-Is reduced surface energy and enlarged the interlayer spacing between rGO nanosheets, ensuring that Re³⁺/SMA-Is/rGO could form a uniform dispersed phase in the organic coating. The anti-corrosion performance of the nanocomposite coating was measured by electrochemical techniques in corrosive medium, revealing that introducing the nanocomposite to epoxy matrix exhibited a significant decline of the increase of corrosion potential and corrosion current density. In all samples, La³⁺/SMA-Is/rGO had the highest anti-corrosion performance, and the protection efficiency on mild steel was up to 98.97%.     

In-situ generation and application of nanocomposites on steel surface for anti-corrosion coating

Thin organic coatings directly on steel sheets provide excellent barrier protection in saline environment and meet deformability demands, but fail in providing active corrosion protection. We have put an effort to solve this problem by formulating composite coatings using in-situ generation of metal oxide nanoparticles (NPs) in the polymer matrix. Here we present a new synthesis method of high performance polyetherimide composite with TiO₂, MgO, and Al₂O₃ nanoparticles and their application for anti-corrosion coatings in saline environment. We observed that in-situ synthesis of these metal oxide NPs in the polymer curing process leads to evenly distribution and uniform size of nanoparticles. Thermo-mechanical property was analyzed for these three kinds of free-standing composite film to assess elasto-plastic behaviour and compared to mother polymer film. Results indicated that thermal stability and elastic behaviour of composites film are not affected to the great extent by the presence of NPs. The potentiodynamic and the electrochemical impedance studies on these composite coated steel panels were carried out to identify active–passive behaviour. Results showed active corrosion protection from nanocomposite coating based on TiO₂ and barrier protection was noticed from nanocomposite coating based on MgO and Al₂O₃.     

Manganese oxide embedded polypyrrole nanocomposites for electrochemical supercapacitor

MnO₂ embedded PPy nanocomposite (MnO₂/PPy) thin film electrodes were electrochemically synthesized over polished graphite susbtrates. Growing PPy polymer chains provides large surface area template that enables MnO₂ to form as nanoparticles embeded within polymer matrix. Co-deposition of MnO₂ and PPy has a complimentary action in which porous PPy matrix provides high active surface area for the MnO₂ nanoparticles and, on the other hand, MnO₂ nanoparticles nucleated over polymer chains contribute to enhanced conductivity and stability of the nanocomposite material by interlinking the PPy polymer chains. The MnO₂/PPy nanocomposite thin film electrodes show significant improvement in the redox performance as cyclic voltammetric studies have shown. Specific capacitance of the nanocomposite is remarkably high (∼620 F g⁻¹) in comparision to its constituents MnO₂ (∼225 F g⁻¹) and PPy (∼250 F g⁻¹). Photoelectron spectroscopy studies show that hydrated manganese oxide in the nanocomposite exists in the mixed Mn(II) to Mn(IV) oxidation states. Accordingly, chemical structures of MnO₂ and PPy constituents in the nanocomposite are not influenced by the co-deposition process. The MnO₂/PPy nanocomposite electrode material however shows significantly improved high specific capacitity, charge-discharge stability and the redox performance properties suitable for application in the high energy density supercapcitors.     

Studying the influence of nano-Al2O3 particles on the corrosion performance and hydrolytic degradation resistance of an epoxy/polyamide coating on AA-1050

The aim of this work was studying the effects of addition of Al₂O₃ nanoparticles on the anticorrosion performance of an epoxy/polyamide coating applied on the AA-1050 metal substrate. For this purpose, the epoxy nanocomposites were prepared using 1, 2.5 and 3.5 (w/w) pre-dispersed surface modified Al₂O₃ nanoparticles. Field-emission electron microscope (FE-SEM) and ultraviolet–visible (UV–Vis) techniques were utilized in order to evaluate the nanoparticles dispersion in the epoxy coating matrix. The anticorrosion performance of the nanocomposites was studied by electrochemical impedance spectroscopy (EIS) (in 3.5 wt% NaCl solution for 135 days immersion) and salt spray test for 1000 h. The coating resistance against hydrolytic degradation was also studied by optical microscope and Fourier-transform infrared spectroscopy (FTIR). Results obtained from FE-SEM micrographs and UV–visible spectra showed that the nanoparticles dispersed in the coating matrix uniformly with particle size less than 100 nm even at high loadings. Results revealed that nano-Al₂O₃ particles could significantly improve the corrosion resistance of the epoxy coating. Nanoparticles reduced water permeability of the coating and improved its resistance against hydrolytic degradation.     

Mica/polypyrrole (doped) composite containing coatings for the corrosion protection of cold rolled steel

Micas/polypyrroles (PPys) doped with molybdate, p-toluene sulfonate, dodecyl benzene sulfonate, and 2-naphthalene sulfonate composite pigments were synthesized by chemical oxidative polymerization and characterized in coatings for corrosion protection on cold rolled steel substrate by various electrochemical techniques. Synthesized composite pigments were characterized for morphology by scanning electron microscopy, which indicated physical formation of PPy on the surface of mica. Chemical composition of the composite pigments was analyzed by X-ray photoelectron spectroscopy which chemically confirmed doped PPy formation on the mica surface. Coatings were formulated at 20% pigment volume concentration (composite pigments or as-received mica pigment) and were applied on cold rolled steel substrate. Coatings were exposed to salt spray test conditions (ASTM B117) for 30 days and were periodically assessed for corrosion with electrochemical impedance spectroscopy (EIS), open circuit potential (OCP), and potentiodynamic polarization. EIS and circuit modeling results demonstrated higher coating resistance (R _c) for mica/PPy (doped) composite coatings as compared to as-received mica pigment containing coating after 30 days of salt spray exposure. Lower current density and more positive corrosion potential values were observed for mica/PPy (doped) composite coatings as compared to mica pigment-based coating in potentiodynamic polarization measurements, indicating improved corrosion protection for cold rolled steel substrate. OCP measurements revealed more positive values for mica/PPy (doped) composite coatings as compared to mica pigment-based coating suggesting superior corrosion protection for mica/PPy (doped) composites.     

Performance of EP/PpPDA and EP/PpPDA/SiO2 nanocomposite on corrosion inhibition of steel in hydrochloric acid solution

Epoxy-poly p-phenylendiamine (EP/PpPDA) and its nanocomposite with SiO₂ nanoparticles (EP/PpPDA/SiO₂) were synthesized and tested as potential corrosion inhibitors of steel in 1 M HCl solution. Performance of EP/PpPDA/SiO₂ and EP/PpPDA coatings on protection of steel against corrosion was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Atomic force microscopy (AFM) and at various temperatures between 298 and 328 K. Changes in the coating resistance and charge-transfer resistance with temperature were analyzed to determine the activation energies of the processes involved. The determined values of activation energy showed that the EP/PpPDA/SiO₂ coating has better anti-corrosion effect than EP/PpPDA. The thermodynamic functions of dissolution processes were also calculated and discussed. The results from AFM observations indicated that the presence of SiO₂ nanoparticles increased the roughness of Epoxy-poly p-phenylendiamine/SiO₂ nanocomposite (EP/PpPDA/SiO₂). It was finally concluded that the presence of silica nanoparticles enhance the protection properties of EP/PpPDA coating as a novel potential corrosion inhibitor for steel.     

Protective properties of PPy‐Au nanocomposite coatings prepared by sonoelectrochemisty and optimized by the Taguchi method

The polypyrrole (PPy) and polypyrrole‐Au (PPy‐Au) nanocomposite films have been sonoelectrochemically synthesized on St‐12 steel electrodes using the galvanostatic technique. Experimental design according to the Taguchi method has been applied to optimize the factors on the synthesis of PPy‐Au nanocomposite coating. Three factors were used to design an orthogonal array L9: Synthesis time (t), Current density (I), and Concentration of HAuCl₄ (C). The synthesized Au nanoparticles during polymerization were characterized by Ultraviolet–visible (UV‐visible) spectroscopy. Characterization of the surfaces was done by scanning electron microscope (SEM), energy dispersive X‐ray spectrum (EDX), and atomic force microscope (AFM). The scanning electron microscopy (SEM) image of PPy shows a smooth surface while PPy‐Au nanocomposite film has a compact morphology. Moreover, energy dispersive X‐ray spectrum (EDX) is evidence for the incorporation of Au nanoparticles. The corrosion protection of coatings was investigated by open circuit potential (OCP) time trends, potentiodynamic polarization technique, and electrochemical impedance spectroscopy (EIS) in a NaCl 3.5% solution. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41087.     

PANI-chitosan-TiO2 ternary nanocomposite and its effectiveness on antibacterial and antistatic behavior of epoxy coating

A straightforward approach has been developed for fabricating antibacterial and antistatic epoxy coatings by using polyaniline-chitosan modified TiO₂ ternary nanocomposite. This nanocomposite was synthesized through the following steps. First, chitosan was grafted onto the TiO₂ nanoparticles and then final nanocomposite was prepared via solution polymerization of aniline. Electrical conductivity measurement revealed that nanocomposite with 7.5 wt % of the modified TiO₂ nanoparticles has noticeably higher conductivity compared to polyaniline. Evaluating the coatings' antibacterial property indicated epoxy coatings with the content of ternary nanocomposite show significant bactericidal activity against Gram-positive bacteria and have acceptable antibacterial action against Gram-negative ones. Also, obtained results showed that the ternary nanocomposite would greatly decrease coatings' surface resistivity and when nanocomposite content is about 2 wt % surface resistivity is about 3 × 10⁷ Ω sq⁻¹. On the contrary, the coating with nanocomposite loading exhibits improved thermal and mechanical performance compared to the coating made of neat epoxy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47629.     

Synthesis of Polyaniline–MnFe2O4–CTAB Nanocomposite in Ionic Liquid: Its Magnetic Properties

Polyaniline–MnFe₂O₄ nanocomposite was successfully synthesized by using 1-butyl-3-methyl-imidazolium bromide (BMIMBr) as ionic liquid and cetyl trimethylammonium bromide (CTAB) as surfactant via in situ polymerization. Structural, morphological, spectroscopic and magnetic properties were investigated by transmission electron microscopy, X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM) respectively. The presence of polyaniline, BMIMBr and CTAB on the surface of the MnFe₂O₄ nanoparticles was confirmed with FT-IR and chemical purity of the product was proved by XRD. The nonmagnetic coating was significantly observed to change the magnetic properties of the product. The magnetic properties such as saturation magnetization, coercivity and remanence magnetization are seen to increase as the temperature decreases. The magnetization curves verify that the sample has ferromagnetic behavior in the temperature range of 10–400 K. Magnetic measurements revealed that product has uniaxial anisotropy instead of expected cubic anisotropy according to the Stoner–Wohlfarth model.     

Electrodeposition of polypyrrole on aluminium in aqueous tartaric solution

The electrosynthesis of polypyrrole (PPy) has been achieved on aluminium in aqueous medium of tartaric acid by means of cyclic voltammetry, potentiostatic and galvanostatic techniques. Scanning electron microscopy (SEM) and X-ray microanalysis by energy spectroscopy dispersion (EDS) applying on surfaces show that the PPy coating is developed from the metal surface through the cracks of the initial Al₂O₃ layer.A mechanism involving the participation of the supporting electrolyte and the pyrrole (Py) in distinct active sites was proposed based on the linear sweep voltammetry. It is observed for all applied electrochemical techniques that the pyrrole concentration has to be higher than 0.1 M to allow the polypyrrole electrodeposition in acid medium.Scanning electron microscopy, secondary electrons (SE) and backscattering electrons (BE), shows that the PPy coating obtained in galvanostatic and potentiostatic modes starts with small islands at weak applied potentials or current densities. Moreover, EDS reveals a good homogeneity and compactness of the film achieved in galvanostatic method. The corrosion results in 3% NaCl medium show that the PPy coating decreases the corrosion behaviour of the aluminium. The bilayer Al₂O₃/PPy shows a capacitor with future applications.     

Room temperature NO2 gas sensor based on PPy/α-Fe2O3 hybrid nanocomposites

Polypyrrole–iron oxide (PPy/α-Fe₂O₃) hybrid nanocomposite sensor films were prepared by spin coating method on glass substrate and characterized for structural and morphological properties by means of X-ray diffraction (XRD), Fourier transform infra red (FTIR) spectroscopy and scanning electron microscopy (SEM), which proved the strong interaction between polypyrrole and α-Fe₂O₃ nanoparticles. The gas-sensing properties of the hybrid nanocomposites were studied and compared with those of PPy and α-Fe₂O₃. It was found that PPy/α-Fe₂O₃ hybrid nanocomposites can complement the drawbacks of pure PPy and α-Fe₂O₃ to some extent. It was revealed that PPy/α-Fe₂O₃ (50%) hybrid sensor operating at room temperature could detect NO₂ at low concentration (10 ppm) with very high selectivity (18% compared to C₂H₅OH) and high sensitivity (56%), with better stability (85%). The sensing mechanism of PPy/α-Fe₂O₃ materials to NO₂ was presumed to be the synergism of PPy and α-Fe₂O₃ or the effect of p–n heterojunctions.     

Structural,electrical, thermal,and gas sensing properties of new conductive blend nanocomposites based on polypyrrole/phenothiazine/silver‐doped zinc oxide

The main aim of this study is to investigate the effect of silver‐doped zinc oxide (Ag‐ZnO) loading on the structural, morphological, thermal and electrical properties, and gas sensing behavior of polypyrrole (PPy)/phenothiazine (PTZ)‐blend nanocomposites. The composites are characterized by FTIR, XRD, SEM, TEM, DSC, TGA, and impedance studies. FTIR spectra exhibit the presence of Ag‐ZnO in the PPy/PTZ blend. XRD analysis shows that the semicrystalline behavior of the polymer blend is greatly enhanced by the addition of Ag‐doped ZnO particles. Uniform dispersion of nanoparticles in the polymer is obtained from SEM analysis. The TEM images confirm the presence of spherically shaped nanoparticles in PPy/PTZ blend with a size of 10–25 nm. The DSC measurement indicates that the glass transition temperature of PPy/PTZ blend was significantly improved in the presence of Ag‐doped ZnO nanoparticles. The thermal decomposition temperature of nanocomposite obtained from TGA shows an increase with increase in the content of Ag‐ZnO particles. The incorporation of Ag‐doped ZnO nanoparticles to PPy/PTZ blend exhibit increase in the AC conductivity and dielectric properties of the nanocomposite, due to the pilling of charges at the extended interface of the composite system. The DC conductivity of the nanocomposite increases with the loading of nanoparticles. The ammonia gas sensing performance of PPy/PTZ/Ag‐ZnO nanocomposite is analyzed, and the result shows that the fabricated blend composite can be used as a promising candidate for the easy access of gas molecules. J. VINYL ADDIT. TECHNOL., 26:187–195, 2020. © 2019 The Authors. Journal of Vinyl and Additive Technology published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.     

Influence of the dopant on the polypyrrole moisture content: Effects on conductivity and thermal stability

Having in mind to produce electrically conductive carbon–epoxy composite materials, we have filled an insulating epoxy resin with an electronic conducting polymer, polypyrrole (PPy). To select the PPy that best suits this process, various PPys were chemically synthesized. The syntheses were performed in water via a dispersion polymerization route using, initially, either FeCl₃ (PPy–Cl⁻) or (NH₄)₂S₂O₈ (PPy–HSO₄⁻) as oxidizing agents. Then, using (NH₄)₂S₂O₈ as the oxidant, two other PPy doped with aromatic species were obtained due to the dissolution of paratoluenesulfonic acid (PPy–TS⁻) or naphtalenesulfonic acid (PPy–NS⁻) in the reaction media. The characterization of the PPy samples by conductivity measurements, together with elemental and thermal analysis, showed that PPy–TS⁻ exhibits the highest conductivity and thermal stability, with the conductivity remaining steady over 14 days. In addition, a stabilizing effect of the aromatic anions was observed. The experiments have shown that moisture in the PPy cannot be entirely removed and that, with increasing moisture content, the conductivity also increases, indicating an ionic conductivity superimposed on the electronic conductivity usually observed in PPy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1567–1577, 1998     

Effects of polymerization medium on electrical conductivity and optical properties of organic semiconductor-based polypyrrole

The effects of tetrabutylammonium tetrafluoroborate (TBAFB), tetrabutylammonium hexafluorophosphate (TBAPF₆), and paratoluene sulfonoicacid (PTSA) polymerization mediums on the electrical conductivity and optical properties of the polypyrrole (PPy) have been investigated. The electrical conductivity and optical properties of the samples polymerized in presence of TBAFB, TBAPF₆, and PTSA organic salts change with medium of prepared polymer. The electrical conductivity of the TBAFB, PTSA, and TBAPF₆ samples at 27°C were found to be 3.43 × 10⁻¹, 4.48 × 10⁻², and 1.60 × 10⁻⁴ (S/cm), respectively. The lowest optical band gap of the polymer was found to be 2.23 eV. The refractive index dispersion of the samples obeys single oscillator model. The obtained results suggest that polymerization medium changes electrical conductivity and optical properties of the PPy. POLYM. ENG. SCI., 47:1016–1020, 2007. © 2007 Society of Plastics Engineers     

Manganese spinel ferrite-reduced graphene oxides nanocomposites for enhanced solar irradiated catalytic studies

An excellent photocatalyst must have narrow band gap value, broad absorption range and high electrical conductivity. The co-precipitation route was followed to synthesize copper substituted manganese ferrite nanoparticles because the co-precipitation is a facile, short and easy to handle method. The nanocomposite of copper substituted manganese ferrite with rGO was synthesized by sonication method. The graphene was used for composite synthesis because of its extraordinary properties such as chemical stability, high transparency, large surface area, high electron transfer ability. Graphene can also improve catalytic acitivity of spinal ferrites. X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM) were employed to confirm the structural, spectral and morphological aspects of prepared nanomaterials and their composites with rGO. XRD confirmed face centered cubic (FCC) crystal structure. The appearance of relative broad peaks estimated the formation of nanocrystalline size of synthesized samples. SEM images showed that the nanoparticles have spherical morphology. Furthermore, rGO sheets can be clearly seen in SEM images of composite material. It was investigated that electrical conductivity of MnF₂O₄ was increased by the substitution of metal cations such as copper. Current – voltage measurements were carried out at room temperature and confirmed the enhanced conductivities of copper doped manganese ferrite and its rGO based nanocomposite. These photocatalysts were used for the degradation of methylene blue (MB) dye and Mn_0.9Cu_0.1Fe₂O₄/rGO nanocomposite showed great activity in photocatalysis experiment with 77% degradation efficiency. This increment in photocatalysis was found to be due to synergistic effect of ferrite material and rGO sheets, which increases the electrical conductivity and decreases the photoexcited electrons-holes pair recombination of composite materials.     

Effect of ceria and zirconia nanoparticles on corrosion protection and viscoelastic behavior of hybrid coatings

Organic–inorganic hybrid nanocomposite coatings contain inorganic particles that are dispersed in organic phase in nanometric dimensions. Ceria and zirconia colloidal dispersions are uniformly distributed in the epoxy silica-based hybrid nanocomposite by sol–gel method and coated on 1050 aluminum alloy substrate with spin-coating technique. The hybrid sol is prepared by organic–inorganic precursors formed by hydrolysis and condensation of 3-glycidoxypropyltrimethoxysilane and tetraethylorthosilicate (TEOS) in acidic solution using bisphenol A as networking agent and 1-methylimidazole as initiator in the presence of various ratios of ZrO₂ and CeO₂ colloidal nanoparticles. Particle size distribution, surface morphology and inorganic components distribution were determined by scanning electron microscopy (SEM) and EDXA techniques. SEM and Si, Zr, Ce mapping micrographs proved the uniform distribution of nanoparticles in the coatings. Transmission electron microscopy indicated that the nanoparticles dimension stay at the nanoscale level. The glass transition temperature (T _g) and loss properties (damping) of coatings were evaluated by dynamic mechanical thermal analysis. The corrosion protection of the coatings on the 1050 AA substrate was studied by potentiodynamic measurements. The results indicated that by introducing ceria nanoparticles in 1:1 molar ratio to TEOS in coating composition, corrosion protection was improved. However, the simultaneous presence of two nanoparticles (i.e., ceria and zirconia in 1:1 molar ratio) in the coating compositions increased the corrosion protection efficiency up to 99.8 %. The multiple glass transitions and shifting to higher and wide range of temperatures by adding ceria and zirconia nanoparticles indicated a better network interaction between inorganic nanoparticles and organic molecular chains which also led to better corrosion protection of the coating in this composition.     

The Ionic Liquid Based Synthesis of Polyaniline–MnFe2O4–CTAB Nanocomposite: Electrical Properties

Polyaniline (PANI)–MnFe₂O₄ nanocomposite was successfully synthesized by using 1-butyl-3-methyl-imidazolium bromide as ionic liquid and cetyl trimethylammonium bromide as surfactant via in situ polymerization. Structural, morphological, spectral and magnetic investigation of the product were done by X-ray powder diffractometry, fourier transform infrared spectroscopy, thermal gravimetric analyzer, transmission electron microscopy, vibrating sample magnetometry respectively. Electrical properties of PANI–MnFe₂O₄–CTAB nanocomposite was characterized with a measurement of an impedance spectroscopy, which was evaluated at frequency range varying from 1 Hz to 3 MHz for temperature range of 20–120 °C. In general ac conductivity remained almost unchanged until it reaches up to 160 kHz, and then reduced slightly almost for all temperatures except for some slight fluctuation somehow.     

Novel carboxyl functional spherical electromagnetic polypyrrole nanocomposite polymer particles with good magnetic and conducting properties

Magnetic conducting nanoparticles with reactive functional groups are attractive materials for applications in electromagnetic interference shielding, magneto‐optical storage, biomedical sensing, gas and humidity sensors, flexible electronics etc. The objective of this work was to prepare carboxyl functionalized polypyrrole (PPy) nanocomposite particles having good magnetic properties. Electromagnetic PPy nanostructures, abbreviated as PPy/γ‐Fe₂O₃, were first prepared by a chemical one‐step method. In this reaction process FeCl₃ is used as an oxidant for the polymerization of pyrrole and as a source of Fe³⁺ for the formation of γ‐Fe₂O₃. The formation of γ‐Fe₂O₃ is also aided by the initial presence of Fe²⁺, and p‐toluenesulfonic acid (p‐TSA) acted as a dopant. The effects of different stabilizers on the stability and morphology of PPy/γ‐Fe₂O₃ particles were evaluated. The presence of citric acid/sodium dodecyl sulfate during chemical oxidative polymerization produced a relatively stable PPy/γ‐Fe₂O₃ colloidal emulsion. PPy/γ‐Fe₂O₃/poly(methylmethacrylate‐methacrylic acid) (PPy/γ‐Fe₂O₃/P(MMA‐MAA)) nanocomposite polymer particles were then prepared by the seeded copolymerization of MMA and MAA in the presence of magnetic PPy/γ‐Fe₂O₃ nanocomposite seed particles. The structure and morphology of the prepared nanocomposites were confirmed by different instrumental techniques such as Fourier transform IR spectroscopy, UV?visible spectroscopy, electron micrographs, XRD and X‐ray photoelectron spectroscopy. The electrical and magnetic properties were also investigated. The carboxyl functional electromagnetic PPy nanocomposite polymer particles should be useful for the immobilization of drugs or biomolecules to design electrically stimulated drug delivery systems for modulating the activities of nerve, cardiac, skeletal muscle and bone cells. © 2016 Society of Chemical Industry