Interface Of Polyaniline Research Articles

Smart Doped Polyaniline Coating for Wireless Anodic Protection of AISI 304 Stainless Steel in a Corrosive Medium Containing Sulfate and Chloride Ions: Electrochemical and DFT Evaluations.

Polyaniline (PANI) coatings have the capability of in situ anodic protection of stainless steels (SSs). However, these coatings have a high degradation rate in sulfuric acid. Also, the protection of SSs in a medium contaminated with chloride ions is an unsolved challenge. Therefore, the present work aims to modify the electrodeposited PANI coating with different dopants to find the optimal coating for the anodic protection of 304 SS in chloride-contaminated sulfuric acid. Thus, CH3COO-, HSO4-, NO3-, H2PO4-, and NaSO4- were doped electrochemically in PANI to determine the most effective corrosion depressor. Density functional theory (DF)T calculations determined that the lowest Gibbs free energy (more spontaneous doping) is for HSO4- doping by 24 kcal/mol. The band gap energy is <0.5 eV for the PANI/H2SO4 coating, indicating the very high conductivity of this coating. Monte Carlo simulation revealed that the highest deformation energy is related to PANI/H2SO4 at 1877 kcal/mol (stronger adsorption). Mott-Schottky and energy-dispersive spectroscopy (EDS) results showed that PANI doped with sulfuric acid creates a p-type semiconductor (Ni-rich), while the rest of the dopants lead to the formation of an n-type semiconductor passive film (Fe/Cr-rich). Despite the relatively low corrosion resistance of PANI/H2SO4 in the early days, its resistance improved over time by more than 1 order of magnitude. Therefore, this seems to be a more favorable option for long-term anodic protection. Thus, in this work, the corrosion behavior of the passive film formed at the interface of PANI and SS was comprehensively evaluated.

Multifunctional characteristics of a one-dimensional bimetallic oxyhydroxide nanorod-coupled polyaniline interface for accelerated water and urea electrolysis

Designing an efficient and durable electrocatalyst is central to hydrogen production technologies such as hydrogen evolution reaction, oxygen evolution reaction, and urea oxidation reaction.

Characteristic studies of Ta3N5/BSC@PANI nanocomposites for hydrogen production via water-splitting under visible light irradiation

Hydrogen (H2) production in water-splitting could be significantly increased by designing cost-effective photocatalysts with remarkable performance. The main objective of this study is to recognize the behavior of soot carbon-based metal nitrides nanocomposites on its photocatalytic activity when exposed to solar lights. This study synthesized a p-n heterojunction Ta3N5/PANI composite photocatalyst modified by eco-friendly and low-cost biomass soot carbon (BSC) using hydrothermal and chemisorption methods. BSC materials are photoactive when exposed to UV light because of their band gap (Eg < 4 eV), indicating they behave as semiconductors. Compared to pure Ta3N5, the hydrogen production rate of a photocatalyst containing polyaniline (PANI) can reach up to 76.9 μmol g−1 h−1, equivalent to 3.42 times superior to pristine Ta3N5. The formation of a p-n heterojunction at the interface of PANI and Ta3N5 was primarily responsible for improving the H2 evolution activity. This successfully prevents the self-photocorrosion of Ta3N5 by providing a rapid route for the migration and separation of photogenerated charges. It also confirms the long-term stability of the materials by repeating the experiments up to 6 cycles with more than 95 %.

Adsorption, Equilibrium Isotherm, and Thermodynamic Studies towards the Removal of Reactive Orange 16 Dye Using Cu(I)-Polyaninile Composite.

To overcome some of the limitations of activated carbon like efficiency, cost-effectiveness, and reusability, the present work deals with Cu(I)-based polyaniline (PANI) composite for the removal of reactive orange 16 (RO16) dye. Following the synthesis and characterization of formed Cu(I)-PANI composite, the batch experiments performed for the removal of RO16 dye indicated that the composite has the capacity to reduce the coloring from RO16. The experiments were conducted for the study of effects against changes in pH, time, and dose at room temperature, where we observed for a pH impact on the dye adsorption capacity in the range of 2–12. Among all, the optimal RO16 removal was found to be 94.77% at a pH of 4 and in addition, the adsorption kinetics confirmed to be pseudo-second-order with more suitability towards the Langmuir isotherm, where it is presumed to be the formation of a monolayer of dye molecule at the homogeneous absorbent surface. The calculated maximum capacity, qm, determined from the Langmuir model was 392.156 mg/g. Further application of isotherms to attain thermodynamic parameters, a slight positive value of ΔS° for RO16 adsorption was observed, meaning that there is an increased randomness in the irregular pattern at the specific Cu(I)-PANI interface for an adsorption process. This mechanism plays an essential role in maintaining the effects of water pollution; and, based on the analysis therefore, it is prominent that the Cu(I)-PANI composite can be employed as a promising and economical adsorbent for the treatment of RO16 and other dye molecules from the sewage in wastewater.

Efficient nickel or copper oxides decorated graphene–polyaniline interface for application in selective methanol sensing

Graphene sheets decorated with nickel or copper oxides that were anchored on polyaniline (denoted as PANI-graphene/NiO and PANI-graphene/CuO) were prepared by a simple, easy to-control electrochemical method and applied as novel materials for sensitive and selective methanol sensing. The fabricated sensors exhibited good electrocatalytic activity, appropriate dynamic linear range (20–1300 mM), sensitivity (0.2–1.5 μA mM−1 cm−2) and excellent selectivity towards methanol. It should be highlighted from the selectivity tests that no significant interference was observed from ethanol and other alcohols. To our best knowledge, using inexpensive but efficient transition metals like Ni, Cu instead of Pt, Pd and their composites with PANI, graphene would be scientifically novel and practically feasible approach for sensor fabrication that could be potentially used to identify methanol adulteration in counterfeit alcoholic beverages.

PREPARATION AND INVESTIGATIONS OF STRUCTURAL, OPTICAL AND CONDUCTIVITY PROPERTIES OF POLYANILINE/TITANIUM DIOXIDE NANOCOMPOSITES

Nanocomposites of polyaniline (PANI) encapsulating titanium dioxide (TiO2) nanoparticles (NPs) were prepared by in-situ polymerization method in the presence of TiO2 NPs. The prepared nanocomposites were analyzed by powder X-ray diffraction (PXRD), uv-visible absorption spectroscopy (UV), Fourier-transform infrared spectra (FTIR) and high resolution transmission electron microscope (HRTEM). An AC conductivity study of PANI/TiO2 nanocomposites was analyzing in between 1 Hz to 8 MHz and a particular temperature 500C. The P-XRD was explaining amorphous nature in PANI/TiO2 nanocomposites respectively. The particle size was observed and confirmed using HRTEM, which shows the formation of nanocomposites at around near in spherical shape in the nanoscale range. An FTIR study confirms the bonding and formation of the prepared samples. FTIR spectral obtained shows that TiO2 and PANI NPs are not simply encapsulated and a strong interaction obtain at the interface of PANI and TiO2 NPs. A UV- vis spectra was used to analysis the confined polymerization process of PANI doped TiO2. The UV absorption spectrum showed a blue shift as compared to the pure TiO2 NPs. AC conductivity measured indicates that the conductivity of PANI/TiO2 nanocomposites is decreased with TiO2 NPs. The AC conductivity of PANI/TiO2 nanocomposites has measured at a 146 S cm-1 . The AC conductivity property is obtained to be changed due to the combine of TiO2 NPs, which induced the formation of a coherent for charging transport in the base PANI chain.

Gold-microrods/Pd-nanoparticles/polyaniline-nanocomposite-interface as a peroxidase-mimic for sensitive detection of tropomyosin

In this study, Gold-microrods (AuMRs), Pd-nanoparticles (PdNPs), and Polyaniline (PANI) nanocomposite-interface was fabricated on the screen-printed carbon-microelectrode (SPE). Each layer of the interface was characterised using field emission-scanning electron microscopy (FE-SEM) and cyclic voltammetry (CV). The fabricated SPE/AuMRs/PdNPs/PANI interface demonstrated the highest electronic current and showed excellent peroxidase-mimic towards H2O2 using chronoamperometry (CA). Furthermore, the SPE/AuMRs/PdNPs/PANI interface was utilised for the construction of a highly sensitive label-free electrochemical biosensor for the detection of Tpm in seafood samples. Label-free electrochemical detection of the Tpm was performed using both CA and differential pulse voltammetry (DPV) techniques. Preliminary data showed that both methods could detect Tpm as low as 0.01 pg/mL. Moreover, the developed biosensor for the detection of Tpm demonstrated excellent selectivity, high reproducibility and longer stability with an evident potential to detect Tpm in real seafood samples.

Reagentless Redox Capacitive Assaying of C-Reactive Protein at a Polyaniline Interface.

Methods that enable the sensitive and label-free detection of protein biomarkers are well-positioned to make potentially significant contributions to diagnostics and derived personalized healthcare. In support of this goal, a myriad of (electrochemical) methodologies have been developed; recently, electrochemical capacitance spectroscopy emerged as an impedance-derived approach which, in employing surface-confined redox-transducers, circumvents problems associated with the use of solution-phase redox-probes. Herein, we expand this scope by utilizing phytic acid-doped polyaniline as a novel redox-charging polymer support enabling the reagentless assaying of C-reactive protein in serum with good sensitivity. The construction of the sensory interface via electropolymerization allows facile tuning of the surface coverage and redox (capacitive) properties of the polymers, which, in turn, modulate both assay selectivity, fouling, and sensitivity. Significantly, this methodology is readily extendable to a wide range of electrode materials and analytes.

Modifying delafossite silver ferrite with polyaniline: Visible-light-response Z-scheme heterojunction with charge transfer driven by internal electric field

Polyaniline (PANI), a conductive polymer with a delocalized π-conjugated structure, high visible light absorption coefficient and superior charge carrier transfer, has been widely used in combination with other semiconductors to improve photocatalytic performance. In this work, novel PANI/AgFeO2 photocatalysts with visible light photocatalytic performance were successfully synthesized by in situ deposition of AgFeO2 nanoparticles on the surface of PANI. The optimal PANI/AFO-0.2 catalyst resulted the highest photocatalytic performance, about 91.8% of TC was degraded after 1 h of visible light irradiation, the degradation rate constant of which was 2.4 and 15.5 times than that of single AgFeO2 and PANI, respectively. The enhanced photocatalytic performance was attributed to the synergistic effect of enhanced visible light absorption, high specific surface area and excellent charge transfer. Most importantly, based on the comprehensive analysis of the Fermi level and bandgap structure of PANI and AgFeO2, it was found that the internal electric field (IEF) established at the contact interface of PANI and AgFeO2 caused photogenerated electrons and holes to migrate along a path similar to the letter “Z”. Therefore, the photogenerated electrons in the CB of AgFeO2 recombined with the equivalent holes generated from the HOMO of PANI, indicating that PANI can also act as an electron acceptor to maximize the strong reducibility of its CB-electrons, which was reported for the first time. As a result, strongly reduced electrons and oxidized holes were retained in PANI and AgFeO2, respectively, leading to an enhanced photocatalytic TC degradation performance. This work provided a novel photocatalyst with excellent visible light photocatalytic performance and investigated the mechanism of interface charge transfer.

In-situ growth of highly permeable zeolite imidazolate framework membranes on porous polymer substrate using metal chelated polyaniline as interface layer

A facile and simple chelation assisted in-situ growth approach for the preparation of thin uniform metal organic framework composite membranes has been developed. Coherent zeolite imidazolate framework ZIF-7 and ZIF-67 layers were successfully grown on porous polypropylene substrate covered with metal-chelating polyaniline interface layer. These membranes exhibited a H2 permeance of 1.6 × 10−7 mol m−2 s−1 Pa−1 and an ideal H2/CO2 separation factor of 7.9. The incorporation of the second organic linker 2-aminobenzimidazole in the ZIF-7 framework afforded ZIF-7-NH2 layer enabling gate-opening and flexibility. This new hybrid ZIF-7-NH2 membrane featured a significantly increased H2 permeance of 4.9 × 10−6 mol m−2 s−1 Pa−1 and an ideal H2/CO2 separation factor of 10.6.

Remarkably enhanced performances of polyaniline/electrochemically surface-treated graphite electrodes with optimal charge transfer pathways for flexible supercapacitor application

We propose a strategy to enhance the electrochemical performances of electrodes by optimizing charge transfer pathways at the current collector/electroactive material interface. A facile method is developed for electrochemical surface treatment of graphite, and the obtained electrochemical surface-treated graphite is utilized as substrate for electropolymerization of polyaniline, which facilitates the construction of high-quality electrical links at the interface of polyaniline and electrochemical surface-treated graphite. Effect of galvanostatic and potentiostatic polymerization on electrochemical properties of polyaniline electrodes is also examined. Electrochemical measurements indicate that the potentiostatically polymerized polyaniline electrode has superior supercapacitive performances. In particular, polyaniline/electrochemical surface-treated graphite electrode exhibits remarkably enhanced electrochemical properties in comparison with polyaniline/graphite electrode, which can be ascribed to the optimized charge transfer pathways at current collector/electroactive material interface for the former. Polyaniline/electrochemical surface-treated graphite electrode achieves a high specific capacitance of 437.9 mF cm−2 at 0.5 mA cm−2. Moreover, the polyaniline/electrochemical surface-treated graphite electrodes are used to assemble a flexible solid-state supercapacitor. The device demonstrates high flexibility, superior supercapacitive performances, and good cycling stability, which holds great promise for use in flexible electronics.

Fabrication of polyaniline sensitized grey-TiO 2 nanocomposites and enhanced photocatalytic activity

Abstract The highly efficient composite photocatalysts composed of grey-TiO 2 and electrically conductive polyaniline (PANI) have been fabricated through an in situ polymerization of aniline in the presence of grey-TiO 2 nanoparticles. The grey-TiO 2 nanoparticles were prepared via a chemical reduction method by reducing bare white-TiO 2 nanoparticles with aluminium powder under nitrogen atmosphere. The morphology, crystalline structure and optical property of these PANI sensitized grey-TiO 2 nanocomposites were investigated, and their photocatalytic activity in the phtocatalytic hydrogen generation and photodegradation of Rhodamine B were evaluated. Compared with grey-TiO 2 , the PANI/grey-TiO 2 nanocomposites showed obviously improved photocatalytic efficiency both in the hydrogen production and the degradation of Rhodamine B. The hydrogen generation rate under simulated sunlight irradiation for PANI/grey-TiO 2 nanocomposites was higher than that of most reported TiO 2 -based species. The photocatalytic mechanism analyses indicated that the PANI served as co-catalysts in promoting separation of photoinduced charges, and photoelectrons and holes can transfer efficiently at interface of PANI and grey-TiO 2 , and thus inhibited the recombination of photo generated electron-hole pairs. This article elucidated a promising colored TiO 2 based system, which can be applied in the photocatalytic reactors induced by sunlight irradiation.

Dielectric and Magnetic Relaxation Behavior in Fe78Si9B13/Polyaniline Composites at Radio-Frequency Range

In this paper, Fe78Si9B13/polyaniline composites with different Fe78Si9B13 content are prepared through cryomilling and pressure molding. The dielectric and magnetic properties are investigated experimentally in the frequency range from 10 MHz to 1 GHz. Both dielectric and magnetic Debye-like relaxation behavior are observed in this frequency range. With the increase of the FeSiB content, the loss peaks in the permittivity spectrum show a redshift, but a blueshift in the permeability spectrum. The results indicate that the loss peak shift has a close relationship with the conductivity and domain wall displacement. As affected by the interface of polyaniline and Fe78Si9B13 particles, the conductivity of composites decrease with the increase of FeSiB content until the formation of 3D network of FeSiB particles, leading to the redshift of the loss peak in the permittivity spectrum. Meanwhile, the blueshift in the permeability spectrum is mainly caused by the domain wall displacement with high damping factor.

Characterizing the oxidation level of polyaniline (PANI) at the interface of PANI/TiO2 nanoparticles under white light illumination

The polymer/nanoparticle interface of polyaniline (PANI)/TiO2 composite was characterized by using Fourier transform infra-red spectrometer imaging system, Raman (both coupled with optical microscope) and UV–vis spectroscopy. During characterization, as white light from the optical microscope impinges on TiO2, it absorbs supra band-gap photons and electron-hole pairs are produced. On accepting the holes, PANI gets oxidized from emeraldine salt form to its next oxidation state that is pernigraniline salt form, leading to a change in color. In optical micrographs this change in color appears as a halo around each TiO2 particle and defines the extent of the oxidized area of PANI, which helps to characterize the extent of oxidation of PANI at the interface of PANI/TiO2. Further studies revealed that the range and extent of oxidation at the interface in polymer depend on the types of dispersions of TiO2 nanoparticles in PANI matrix.

A tunable metal-polyaniline interface for efficient carbon dioxide electro-reduction to formic acid and methanol in aqueous solution.

It is reported that metals on polyaniline (PANI) prepared by a simple method can exhibit excellent activity in the electro-reduction of CO2 to HCOOH or CH3OH due to tunable properties: N atoms on PANI capture CO2 through a strong Lewis acid-base interaction while Pd atoms, amongst Pd, Pt, and Cu studied, facilitate the fastest proton and electron transfers along PANI to the CO2 trapped sites to give rise to the best HCOOH yield in a highly cooperative manner.

Uniform Polyaniline Nanotubes Formation via Frozen Polymerization and Application for Oxygen Reduction Reactions

A frozen polymerization technique to prepare uniform polyaniline (PANI) nanotubes is reported, based on the concept of the Kirkendall effect that has been successfully applied for preparation of inorganic hollow nanostructures. Specifically, PANI nanotubes with a uniform diameter of 45 nm are prepared by combination of freezing and templating to control the diffusion of aniline and ammonium persulfate at the PANI interface. Due to the low entropy diffusion at solid state and polymerization at low temperature, ordered packed anilines and high crystalline PANI nanotubes are obtained, which greatly facilitate the conversion to conductive nanotubes with nanoscale graphitic domains at low carbonization temperature. The resulting conductive nanotubes exhibit improved catalytic performance in oxygen reduction reactions, suggesting the high potential application of the frozen polymerization technique in preparation of high performance PANI nanostructures. image

Abnormally enhanced thermoelectric transport properties of SWNT/PANI hybrid films by the strengthened PANI molecular ordering

Single-walled carbon nanotube (SWNT)/polyaniline (PANI) hybrid films were prepared by casting the suspension containing well-dispersed SWNTs and CSA-doped PANI. The electrical conductivity of the SWNT/PANI film at first increased with the increasing SWNT content and then decreased at high SWNT content, whereas the Seebeck coefficient increased monotonically in the present SWNT content range. Moreover, the electrical conductivity values of the SWNT/PANI composites were much higher than the values calculated based on the series-connected two-component mixture model, whereas the dependence of the Seebeck coefficient on the SWNT content fitted well with the mixture model. Thermal conductivities increased with the SWNT content, but the rate of increase was much lower than the values estimated using the mixture model. The maximum values of electrical conductivity and Seebeck coefficient of hybrid films were up to 769 S cm−1 and 65 μV K−1. Consequently, the maximum thermoelectric power factor and ZT value at room temperature reached 176 μW m−1 K−2 and 0.12, respectively. The optimal TE property of the SWNT/PANI hybrid film was remarkably higher than those of either individual component of the composite, and exhibits the highest values for inorganic–organic composite materials reported so far. XRD and Raman analyses revealed that the PANI molecules in the composite film had a more expanded conformation, and were more orderly arranged compared with both pure PANI bulk and pure PANI film. The abnormally enhanced thermoelectric performance is attributed to the highly ordered PANI interface layer on the SWNT surface, which formed by the synergetic effect of chain expansion by the chemical interactions between PANI and the solvent and chain-ordering due to the π–π conjugation between PANI and CNTs.

Design and synthesis of the polyaniline interface for polyamide 66/multi-walled carbon nanotube electrically conductive composites

A polyaniline interface had been designed and built between multi-walled carbon nanotubes (MWCNTs) and polyamide 66 (PA66) in order to help in the dispersion of MWCNTs in PA66 and improve the interfacial combination between them. Transmission electron microscopy characterizations indicated that functionalized MWCNTs (f-MWCNTs) could be well-distributed in PA66 matrix and the interfacial boundary between them was indiscernible. The mixing conditions, such as f-MWCNT content, temperature, and mixing speed, played important roles in determining the formation of the conductive network and the electrical conductivities of PA66/f-MWCNT composites synthesized. A continuous conductive network was formed at 10 wt% f-MWCNT content, and the corresponding PA66/f-MWCNT composite exhibited an electrical conductivity of 8 orders of magnitude higher than pure PA66. The conducting mechanism agreed well with a thermal fluctuation-induced tunneling model.

Synthesis, Characterization and Corrosion Protection Properties of Polyaniline/TiO&lt;sub&gt;2&lt;/sub&gt; Nanocomposite

In this study, conductive polyaniline (PANi)–titania (TiO2) nanocomposites with core–shell structure were prepared and their anticorrosion properties were investigated. PANi/nano-TiO2 composite were prepared by in situ polymerization of aniline monomer in the presence of TiO2 nanoparticles. The morphology and structure of the polymer nanocomposite was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. SEM and FTIR spectra measurements show that PANi and TiO2 nanoparticles are not simply blended or mixed up, and a strong interaction exists at the interface of nano-TiO2 and PANi. From the anticorrosion investigation in 3.5%NaCl, it is revealed that the protective performance of epoxy paint containing PANi/nano-TiO2 composite is significantly improved than PANi or a mixture of polyaniline and nano-TiO2. From the improved anticorrosion performance, it also indicate that PANi and TiO2 nanoparticles are not simply blended or mixed up, the strong interaction exists at the interface of PANi and nano-TiO2. It is the strong interaction that results in the coordinated effect and more excellent anticorrosion performance.

Enhancement of photoelectric catalytic activity of TiO 2 film via Polyaniline hybridization

A Polyaniline (PANI)/TiO 2 film coated on titanium foil was successfully prepared using the sol–gel method followed by a facile chemisorption. Compared with pristine TiO 2, the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation rates of 2,4-dichlorophenol (2,4-DCP) with the PANI/TiO 2 film were enhanced by 22.2% and 57.5%, respectively. 2,4-DCP can be mineralized more effectively in the presence of PANI/TiO 2 film. The best PEC degradation efficiency of 2,4-DCP with the PANI/TiO 2 film was acquired at an external potential of 1.5 V with a layer of 1 nm thick PANI. The PANI/TiO 2 film was characterized by Raman spectra, Fourier transform infrared spectra (FT-IR), Auger electron spectroscopy (AES), and electrochemical analysis. These results indicated that there was a chemical interaction on the interface of PANI and TiO 2. This interaction may be of significance to promote the migration efficiency of carriers and induce a synergetic effect to enhance the PC and PEC activities.