PANI Film Research Articles

Synthesis in phytic acid medium and application as anticorrosive coatings of polyaniline-based materials

Polyaniline (PAni) and PAni/jackfruit latex (Lx) were chemically synthesized in a modified medium, namely aqueous phytic acid (HPhy), in order to obtain effective anticorrosive coatings. Spectroscopic, microscopic and diffractometric results show that PAni structure and morphology are altered because of the acid medium and the presence of latex. Electrochemical assays show that coating ennobles carbon steel surface, however the films are permeable to the electrolytic solution. In addition to that, PAni films shifted corrosion potential (Ecorr) of carbon steel to nobler values (ΔEcorr up to 663mV in the case of PAni/Lx blend) and they presented high adherence to the metal surface, as observed by optical microscopy. The polymeric materials synthesized in HPhy medium were more effective as protective coatings than the one synthesized in H2SO4 medium. The performance of those materials suggests that they can be used as primers for protection of steel surfaces. Moreover, the obtained materials can be likewise appropriate anticorrosive coatings for other metallic materials.

Physico-chemical effects of supercritical carbon dioxide post polymerization treatment on HCl-doped polyaniline prepared via oxidative chemical polymerization

Polyanilinefilms doped with varying HClconcentrations (0.2 M, 0.6 M and 1.0 M) were synthesized on glass substrates via oxidative polymerization of aniline. The films were treated with supercritical carbon dioxide (SC-CO2) at 30 MPa and 40°C for 30 minutes. Their structural, optical and morphological properties were studied and compared to conventionally prepared polyanilinefilms using FTIR analysis, UVVisspectroscopy and scanning electron microscopy. It was observed that supercritical carbon dioxide (SC-CO2) could interact with PANI films that consequently altered the bandgapsand changed the film thickness. SC-CO2 treatment also increased the oxidation level of polyanilinefilms and modified the morphology of polyanilinefilm doped with 1M HCl.

Effect of supercritical carbon dioxide treatment on the polarons of HCl‐doped polyaniline films

AbstractIn situ HCl‐doped polyaniline films were synthesized on glass substrates via chemical oxidative polymerization of aniline using ammonium peroxydisulfate as oxidant. The films were treated with supercritical carbon dioxide (SC‐CO2) at 30 MPa and 40 °C for 30 minutes. The physico‐chemical and electrical properties of the films were determined to establish the effect of supercritical carbon dioxide treatment on the polaron structures of polyaniline films. The treatment removed limited number of polarons which affected the properties of polyaniline. The treated films remained conducting despite that the conductance decreased substantially. The treatment enhanced the quinoid character of the films and altered the HOMO‐LUMO transitions. In addition, SC‐CO2 treatment was unable to remove the PANI precipitations adhering on the surface of the films. A mechanism on the effect of SC‐CO2 interaction to HCl‐doped PANI films was proposed. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Nickel coated flyash (Ni-FAC) cenosphere doped polyaniline composite film for electromagnetic shielding

A solid waste material fly ash cenosphere (FAC) was nickel coated and polyaniline in situ polymerized at −30 ± 2 °C in nitrogen atmosphere. A thin film of this composite material was prepared by solution processing and surface morphology/topography was studied. High electromagnetic shielding effectiveness (SE) was obtained for this film; 59 ± 4 μm and 133 ± 4 μm films show an average of 38 and 60 dB SE, respectively, in the frequency range 8.2–12.4 GHz (X-band). Unlike PANI film, the SE of these composite films is high at high frequency. The presence of magneto dielectric microsphere (Ni-FAC) increases the heterogeneity of the composite film in an efficient way for EMI shielding by changing film topography and increasing ac conductivity and permeability.

Investigation of polyaniline films doped with Fe3+ as the electrode material for electrochemical supercapacitors

H+ and Fe3+ ions co–doped polyaniline were synthesized by cyclic voltammetry onto the stainless steel mesh with various concentration of ferric chloride (FeCl3·6H2O) in electrolyte. The structure and morphology of PANI and PANI/Fe3+ films were characterized by Fourier transform infrared (FT–IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical properties of PANI and PANI/Fe3+ films were investigated by cyclic voltammetry, galvanostatic charge–discharge test and electrochemical impedance spectroscopy (EIS) in 0.5molL−1 H2SO4 electrolyte in three–electrode system. The PANI/0.2M Fe3+ film shows a larger specific capacitance of 602F g−1 at a current density of 3mA/cm2 and lower resistance compared with the pure PANI film. The relationship between electrochemical properties of a serious of transition metal ions doped PANI/Mn+ (Mn+=Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Fe3+) films and the ratio of electronic affinity and ionic radius (Ea/r) has also been researched.

Effect of TiO<sub>2</sub> Thin Film Morphology on Polyaniline/TiO<sub>2</sub> Solar Cell Efficiency

Nanocrystalline titanium dioxide (TiO2) thin films were prepared by using sol-gel through spin- coating method. An assembly of indium tin oxide (ITO)/TiO2/polyaniline (PANI)/Ag was made in a sandwich panel structure. The obtained junction shows rectifying behavior. Additionally, the I/V characteristic indicates that a P-N junction at nanocrystalline PANI/TiO2 interface has been created. In this experimental study, we depended only on the ratio between titanium and PANI in the process of preparing sol-gel (PANi/TiO2 at 20% wt). The largest open circuit voltage of 656 mV and short current density of 0.00315 mΑ/cm2 produce 0.0004% power conversion solar cell (η) under simulated solar radiation (50 mW/cm2). The thin films of PANI and titanium oxide (TiO2)/ PANI composites were synthesized by sol-gel technique. Pure TiO2 powder with nanoparticle size of less than 25 nm and PANI were synthesized through chemical oxidative polymerization of aniline monomers. The composite films were characterized by high resolution X-ray diffraction, Fourier transform infrared spectroscopy, field effect scanning electron microscopy, and UV-vis spectroscopy. The results were compared with the corresponding data on pure PANI films. The intensity of diffraction peaks for PANI/TiO2 composites is lower than that for TiO2. The characteristic of the FTIR peaks of pure PANI shifts to a higher wave number in TiO2/PANI composite, which is attributed to the interaction of TiO2 nanoparticles with PANI molecular chains.

Elucidating the deprotonation of polyaniline films by X-ray photoelectron spectroscopy

Incubation of PANI films in physiological conditions leads to deprotonation and loss of dopant from the polymer backbone.

Electropolymerized polyaniline/manganese iron oxide hybrids with an enhanced color switching response and electrochemical energy storage

The PANI/MnFe2O4 nanocomposite film exhibits enhanced coloration efficiency and capacitance compared to the pristine PANI film.

NiS/SnS Core-Shell Embedded Polyaniline Composite: Synthesis and Characterization

Solar cell is a key topic of energy technology research. Recently, low dimensional nanostructure has brought up much attention to fabricate photovoltaic devices. Using nanostructure materials can improve not only efficiency but reduce the cost and size. The room temperature synthesis and characterization of the conducting polyaniline (Pani) films embedded with Co 2+ doped, PVA capped NiS/SnS core-shell particles as photoluminescent boosters is reported. The photoluminescence intensity of the core-shell particles-Pani film had increased significantly. The scanning electron micrographs revealed core-shell structure and their periodic arrangement in the polymer matrix. The charge transfer resistance of the film was found to be 438 Ω. Periodic arrangement of the nanoclusters of the core-shell particles in the continuous conductive polymer matrix and high carrier density promise this material for the photovoltaic applications.

전기화학적 중합온도가 Binary 도핑된 키랄 Polyaniline 모폴로지에 미치는 영향

Binary-doped conducting chiral polyaniline (PAni) was synthesized by electrochemical polymerization of ani- line at low-temperature (0 o C) and room-temperature (RT) conditions. (+)-Camphorsulfonic acid (CSA) and hydrochloric acid (HCl) were used as a binary dopant. Formation of the binary-doped PAni rather than a mixture of the corresponding single- doped PAni was confirmed by cyclic voltammogram, FT-IR and circular dichroism spectra. The temperature influenced the electrochemical behavior and doping level, thus determining the crystallinity and morphology of the PAni. However, among other results, morphology of the PAni is found to be most strongly depends on the polymerization temperature. With increased temperature from the initial state to RT, morphology of the PAni changed from fibrous to short-fibrous structure. The sheet resistance of the PAni films on an ITO was measured by using four-point probe dc method.

A high performance all-organic flexural piezo-FET and nanogenerator via nanoscale soft-interface strain modulation.

Flexural strain fields are encountered in a wide variety of situations and invite novel device designs for their effective use in sensing, actuating, as well as energy harvesting (nanogenerator) applications. In this work we demonstrate an interesting all-organic device design comprising an electrospun P(VDF-TrFE) fiber-mat built directly on a conducting PANI film, which is also grown on a flexible PET substrate, for flexural piezo-FET and nanogenerator applications. Orders of magnitude stronger modulation of electrical transport in PANI film is realized in this device as compared to the case of a similar device but with a uniform spin-coated P(VDF-TrFE) film. We find that in the flexural mode of operation, the interaction between the laterally modulated nanoscale strain field distributions created by the fibers and the applied coherent strain field strongly influences the carrier transport in PANI. The transport modulation is suggested to occur due to strain-induced conformational changes in P(VDF-TrFE) leading to changes in carrier localization-delocalization. We further show that the fiber-mat based device system also works as an efficient nanogenerator capable of delivering power for low power applications.

Development of Polyaniline Using Electrochemical Technique for Plugging Pinholes in Cadmium Sulfide/Cadmium Telluride Solar Cells

Polyaniline (PAni) thin films were prepared by using an electrochemical polymerization technique on glass/FTO substrates by varying the deposition potential, deposition time, pH concentrations and heat treatment conditions. The structural, morphological, optical and electrical properties of electrodeposited PAni films were characterized using x-ray diffraction, scanning electron microscopy, UV–VIS spectroscopy, optical profilometry and D.C. conductivity measurements. Structural analysis shows the formation of the highest crystallinity for PAni thin film grown at V g 1654 mV. Optical absorption measurements have demonstrated a wide variety of energy band gaps (E g), varying from ∼0.50 eV to 2.40 eV for PAni grown by tuning the pH value during the deposition. The electrical resistivity showed an increase from 0.37 × 106 Ω cm to 3.91 × 106 Ω cm when the pH increased from 2.00 to 6.50. The diode structures of glass/FTO/CdS/CdTe/PAni/Au were fabricated incorporating PAni as a pinhole plugging layer, and assessed for their photovoltaic activities. The results showed the enhancement of all device parameters, especially of open circuit voltage and fill factors. This improvement offers a great potential for enhancing solar cell performance and the device lifetime, and the latest results are presented in this paper.

Hybrid polyaniline–TiO2 nanocomposite Langmuir–Blodgett thin films: Self‐assembly and their characterization

ABSTRACTPolyaniline (PANi)–titanium dioxide (TiO2) nanocomposite materials were prepared by chemical polymerization of aniline doped with TiO2 nanoparticles. Surface pressure–area (π‐A) isotherms of these nanocomposites show phase transformations in the monolayer during compression process. Multiple isotherms indicate that the monolayer of the nanocomposite material can retain its configuration during compression‐expansion cycles. Langmuir–Blodgett thin films of PANi–TiO2 nanocomposite were deposited on the quartz and indium tin oxide coated conducting glass substrates. Fourier transfer infrared spectroscopy and UV–visible spectroscopy study indicates the presence of TiO2 in PANi, whereas X‐ray Diffraction study confirmed the anatase phase of TiO2 and particle size (∼nm) of PANi–TiO2. The morphology of Langmuir–Blodgett films of these nanocomposites was also characterized by atomic force microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41386.

High efficiency electrochemiluminescence from polyaniline:ruthenium metal complex films

Electrochemiluminescent films have been formed by electrodepositing polyaniline, PANI, in the presence of [Ru(bpy)2PIC]2+; bpy is 2,2′-bipyridyl and PIC is (2,2′-bipyridyl)-2(4-carboxylphenyl) imidazo [4,5][1,10] phenanthroline. The homogeneous charge transport diffusion coefficient, DCT, for the Ru2+/3+ couple within the PANI film is 2.6±0.9×10−10cm2s−1. The large DCT facilitates a fast regeneration of Ru3+ and, coupled to a relatively rigid microenvironment, results in a high ECL intensity in the presence of tripropylamine as a co-reactant compared to [Ru(bpy)3]2+. Significantly, despite the conducting nature of the polymer backbone, the [Ru(bpy)2PIC]2+ loaded PANI has the highest efficiency, 1.00%, yet reported for a surface confined ruthenium complex.

Quartz crystal microbalance VOCs sensor based on dip coated polyaniline emeraldine salt thin films

Quartz crystal microbalance (QCM) technique has been used to detect a number of aromatic volatile organic compounds (VOCs) vapors widely used in research and industrial fields. Detection was based on dip coated polyaniline emeraldine salts (PANI-ES) thin films doped with three different acids, i.e. hydrochloric acid (HCl), dodecylbenzene sulfonic acid (DBSA) and 1,5-naphtalene disulfonic acids (1,5-NDSA)) on AT-cut 10MHz QCM electrode. Frequency change was recorded upon adsorption and desorption of (VOCs) on PANI films. It was found that frequency shifts varied linearly with both vapor concentration in part per million (ppm) and film thickness in nanometer (nm). Frequency changes are assumed to be mainly due to electrostatic interactions established between vapor molecules and dopant agents within PANI-ES films. Particularly, PANI-DBSA films were found to be highly sensitive (∼7Hz/ppm), selective to para-xylene (over toluene and benzene) and have a limit of detection of 3ppm. Interestingly, the films exhibit excellent recovery within less than 3min.

Enhanced thermal stability under DC electrical conductivity retention and visible light activity of Ag/TiO₂@polyaniline nanocomposite film.

The development of organic-inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO2@Pani nanocomposite film via a simple biogenic-chemical route. Electrically conducting Ag/TiO2@Pani nanocomposites were prepared by incorporating Ag/TiO2 in N-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO2@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO2@Pani nanocomposite was confirmed by UV-visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO2@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO2@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future.

Magnetic and electromagnetic properties of Pr doped strontium ferrite/polyaniline composite film

This paper reported three acid (including hydrochloric acid HCl, p-toluenesulfonic acid PTS and D-camphor-10-acid CSA) doped SrPr0.2Fe11.8O19/PANI composite film and the HCl–PANI film prepared by a sol–gel method and in-situ oxidative polymerization. The characteristics of the film phase structure, surface morphology, conductivity and magnetic and electromagnetic properties were studied by using XRD, XPS, FESEM, four-probe tester, VSM and Vector Network Analyzer. The resistivity of organic acid doped composite films is higher than that of the HCl doped one. The saturation and remanent magnetization of PTS and HCl doped composite films are greater than the CSA-doped one; however, the coercivity of the three acid doped composite films is basically 5546Oe. The saturation magnetization, remanent magnetization and coercivity of SrPr0.2Fe11.8O19 film are greater than those of the SrPr0.2Fe11.8O19–PANI composite film. In the frequency range of 8–12GHz, the dielectric loss of HCl–PANI film is the maximum, and the dielectric loss of SrPr0.2Fe11.8O19 film is the minimum; the magnetic loss of the four films is in descending order as SrPr0.2Fe11.8O19 film, PrSrM/(HCl–PANI) composite film, PrSrM/(CSA–PANI) and HCl–PANI film.

Electrically conductive and optically transparent polyaniline/montmorillonite nanocomposite thin films

Simple technology (i.e. one-step polymerization of anilinium sulfate in the presence of montmorillonite) has been used to prepare polyaniline/montmorillonite (PANI/MMT) nanocomposite thin films. The present work is focused on the effect of MMT content on the thickness, morphology and electrical conductivity of PANI/MMT nanocomposite films. An increase in MMT content led to an increase in film thickness and surface roughness and to a decrease in conductivity from a maximum value of 356S/m to a minimum value of 76S/m, while for pure PANI films, prepared using the same polymerization procedure (from anilinium sulfate), the conductivity was 59S/m. On the other hand, the MMT content exhibited a significant impact on the optical transparency of PANI/MMT nanocomposite films, which was limited to the range of 450–650nm in contrast with pure PANI films showing non-zero transparency in the whole measured range of wavelength 300–800 nm. Atomic force microscopy clearly proved the alignment of PANI chains in nanocomposite films in comparison with pure PANI films. Scanning electron microscopy revealed in detail the significant difference in surface morphology between pure PANI films and PANI nanofilms covering the MMT particles.

Decoration of reduced graphene oxide with polyaniline film and their enhanced microwave absorption properties

The composites of reduced graphene oxide-polyaniline film (RGO-PANI) were synthesized by an in situ polymerization method and the microwave absorption properties of the composites were investigated. FESEM results indicate that RGO is covered with polyaniline film, and some PANI nanoparticles with the diameter in the range of 10–30 nm embed in the film. As PANI film covered on RGO, the microwave adsorption properties of RGO are significantly enhanced. The maximum reflection loss of RGO-PANI is up to −41.4 dB at 13.8 GHz and the bandwidths exceeding −10 and −20 dB are 4.2 GHz (from 11.7 to 15.9 GHz) and 1.5 GHz (from 12.8 to 14.3 GHz) with a coating layer thickness of 2 mm. The excellent microwave absorption properties of the composites may be attributed to the unique structural characteristics and the charge transfer between RGO and PANI film. Thus, the composites can be used as an attractive candidate for the new type of microwave absorption materials.

New Nanocomposite Materials by Incorporation of Nanocrystalline TiO2 Particles into Polyaniline Conductive Films

This work is focused on the combination of two building-blocks, nanocrystalline TiO2 particles and polyaniline conductive films (PAni). The preparation of new nanostructured composite materials, displaying electron- and proton-conductive properties, to be used for the fabrication of new and superior energy storage devices was envisaged. The semiconducting TiO2 nanoparticles were obtained by means of a hydrothermal route. The PAni films were prepared on glassy carbon electrodes by electrochemical polymerization, under potential dynamic conditions. After characterization by X-ray diffraction, transmission electron microscopy or scanning electron microscopy and electrochemical techniques, the nanocrystalline particles were immobilized in the polymer matrix. The incorporation of the TiO2 was achieved using two distinct approaches: during the polymer growth or by deposition over previously prepared PAni films. The results demonstrate that the PAni morphology depends on the experimental conditions used during the polymer growth. After TiO2 immobilization, the best electrochemical response was obtained for the nanocomposite structure produced through the TiO2 incorporation after the PAni film synthesis. The modified electrodes were structurally and morphologically characterized and their electro-catalytic activity towards the hydrogen evolution reaction was analyzed. A new electrochemical performance related with the oxidation of molecular hydrogen entrapped in the PAni-TiO2 matrix was observed for the modified electrode after TiO2 incorporation. This behavior can be directly associated with the synergetic combination of the TiO2 and PAni, and is dependent on the amount of the semiconductor.