Use Of Polyaniline Research Articles

Optimizing pH sensor performance with PANI/PMMA composite thin films: Impedimetric and capacitive transduction approaches

The continuous search for novel materials to meet the requirements of modern technological applications has led to the widespread use of polyaniline (PANI) composites for sensing purposes. Although research has been carried out on both chemical sensors using PANI/polymer composites and chemical sensors with impedimetric/capacitive transduction using PANI composites, there is still a gap in the use of PANI/polymer composites in impedimetric and capacitive transduction platforms for pH sensing. In this study, the influence of composite thin films consisting of PANI and poly(methyl methacrylate) (PMMA) on the sensitivity and linearity of pH sensors based on electrochemical impedance and capacitance spectroscopy (EIS/ECS) was evaluated. The sensitivity and linearity of the devices showed a dependence on the polymer content. For PANI:PMMA equal to 30:70, the EIS and ECS sensitivity reached 12.6 ± 2.7 and 18.7 ± 4.9 %/pH, respectively, after reaching its minimum value for the 50:50 sample. Similarly, the linearity values for the 30:70 sample were 92.7 % and 99.8 % for EIS and ECS, respectively. We were able to encapsulate the PANI in the PMMA matrix, which improved the control of ion diffusion and analyte access to the active redox quinoid rings on the PANI. As a result, the saturation effect of the polymer was reduced. By adjusting the relative content of PANI and PMMA, the structure and properties of the composite can be controlled, directly affecting the sensor parameters. These materials have potential applications in sensors for various fields such as food, biomedical and environmental monitoring, with the ability to tailor their properties for optimal response.

Halochromic Polyaniline as smart detector packaging for fresh food: a review

Abstract Early spoilage is a challenge that is often encountered in fresh food. One prevention that can be done is by using packaging technology. There has been an increasing interest in using smart detector packaging for fresh products. Smart detector has high sensitivity and is responsive to visual changes when exposed to pH, temperature, water activity, or composition. The advantage of using a smart detector is that it can detect and give information on which products are safe to consume and which are not. Overall, the concept of a smart detector is not much different from the function of smart packaging. Smart packaging that is sensitive to pH is called halochromic properties. The mechanism of halochromic depends on the compound or the indicator used. Polyaniline (PANI) is one of the candidates for halochromic materials, which have high stability and sensitivity to pH changes. PANI also has a high sensitivity to volatile compounds such as ammonia, indicated by a change in colour from green to blue. This review will overview the use of PANI as a smart detector halochromic packaging and its potential application in the food industry. It has been found that the application of PANI has opportunities to advance the development of modern smart packaging and better food quality monitoring systems.

Polyaniline–Titanium Dioxide Heterostructures as Efficient Photocatalysts: A Review

This review paper focuses on present issues concerning the use of polyaniline–TiO2 heterostructures as potentially efficient photocatalysts. Conducting polymers such as polyaniline (PANI) are used in the preparation of heterojunction systems with metal oxides like titania to overcome their inherent limitations, e.g., their sole absorption of UV light and overly fast recombination of charge carriers. This review discusses preparation methods, the properties of resultant products and mechanistic aspects. An important part of this paper is its presentation of the major challenges and future perspectives of such photocatalytic materials.

Electrodialysis Separation and Selective Concentration of Sulfuric Acid and Nickel Sulfate Mixed Solution Using Membranes Modified by Polyaniline

The paper discusses the electrodialysis treatment of mixed nickel sulfate and sulfuric acid solution using polyaniline surface-modified cation exchange membranes. The modified membranes are obtained on the basis of industrial cation-exchange MK-40 heterogeneous and MF-4SK homogeneous membranes by in situ oxidative polymerization of aniline under electrodialysis conditions. The conductive and diffusion characteristics of the initial and modified membranes in solutions of sulfuric acid and nickel sulfate are studied. It is shown that the modification of membranes with polyaniline leads to a decrease in their electrical conductivity and diffusion permeability while maintaining high selectivity. The diffusion permeability of cation-exchange membranes is higher in nickel sulfate solutions compared to sulfuric acid one, while an inverse dependence is found for anion-exchange membranes. The competitive transfer of sulfuric acid and nickel sulfate during electrodialysis separation and concentration of their mixture using initial and modified cation-exchange membranes paired with anion-exchange MA-41 membrane are studied. It is shown that the applying a polyaniline layer with positively charged groups on the surface of the MK-40 or MF-4SK cation-exchange membranes suppresses the transport of doubly charged nickel ions both in the separation and concentration modes over the entire range of current densities. The greatest repulsion effect is observed for homogeneous modified membranes, where the selective permeability coefficient P(H2SO4/NiSO4) increases from 0.7–1.7 to 32.5–19.7 depending on the current density. It is established that the use of polyaniline modified cation-exchange membranes permits to concentrate the solution containing 0.1 mol-eq/L (4.9 g/L) H2SO4 and 0.1 mol-eq/L (7.7 g/L) NiSO4, with simultaneous separation into sulfuric acid with concentration about 2.4 mol-eq/L (120 g/L) and nickel sulfate solutions. The content of nickel sulfate in the concentrate does not exceed 0.13 mol-eq/L (10 g/L).

Comparative electroanalytical performance of poly o‐toulidine and polyaniline towards hydrazine oxidation supplemented by DFT

AbstractThis work presents a comparative experimental and theoretical study on the use of polyaniline and its derivative, poly o‐toluidine, as effective electrochemical sensor for the detection of hydrazine. Hydrazine is a toxic analytic with numerous adverse health effects on the human brain, liver and nervous system. The conducting polymers polyaniline (PANI) and poly o‐toluidine (POT) were synthesized by oxidative polymerization and characterized through x‐ray Diffraction, FT‐IR, and UV–Visible Spectroscopy. Electrochemical studies performed on the polymer modified glassy carbon electrode (GCE) using cyclic voltammetry and differential pulse voltammetry reveal strong interaction between hydrazine and the polymer through irreversible charge transfer. The oxidation current was seen to increase with increasing hydrazine concentration. The diffusion coefficients were found to be 1.89 × 10−5 cm2/s and 2.89 × 10−6 cm2/s for PANI and POT, respectively. PANI and POT based sensors show a limit of detection of 1 μM and 5.13 mM, respectively in the linear concentration range of 1–9 mM. Density functional studies on the PANI‐hydrazine and POT‐hydrazine complexes show enhanced intermolecular charge transfer from nitrogen lone pairs in hydrazine to the polymer backbone clearly identifying the donor and acceptor moieties. PANI based electrochemical sensor is shown to have a higher sensitivity for hydrazine compared to POT, where the sensing interaction is hindered by the bulky methyl group in ortho position.

Applications of Polyaniline–Alkaline Copper Carbonate Composites for Anti-Bio-Attachment of Concrete in Marine Environments

This study proposed the use of polyaniline–alkaline copper carbonate composites as anti-corrosion and anti-biofouling concrete additives and established a set of high-dispersion preparation methods for this composite additive. The effects of polyaniline–alkaline copper carbonate composites in concrete were investigated in marine environments via the preparation of concrete specimens, actual sea suspension experiments, concrete mechanical property tests, and biological attachment avoidance tests. The experimental results showed that (1) the yield of the chemical reactions leading to the preparation of the composite was above 96.46% with a good output. The composite was hydrophilic. The addition of ethylene carbonate as a surfactant and the mixing of the composite into the concrete in a suspension form enabled uniform dispersion of the composite. (2) In the sea waters of Zhoushan, China, bio-attachment was mainly dominated by barnacles and sea anemones. Polyaniline–alkaline copper carbonate composites had good anti-bio-attachment properties and could significantly reduce the amount of bio-attachment in concrete. (3) When the additive content was less than 0.20% of the concrete mass, it did not negatively affect the mechanical properties of the concrete specimens and exerted anti-corrosion and anti-biofouling effects. This reduced the strength loss of concrete and increased the service life of the concrete specimens in the ocean. To ensure the best application effect of the compound in concrete, the recommended content of the compound is 0.05–0.15% of the concrete mass.

Sustainable and Renewable Nano-biocomposites for Sensors and Actuators: A Review on Preparation and Performance

BACKGROUND:Nano-materials derived from sustainable and biodegradable polymers, are the most attractive materials among the researchers. Polymeric nano-biocomposites (PNBCs) are a specific class of materials derived by combining nanosized fillers with polymer materials and the most commonly used nano-fillers were hydroxyapatite, organic or inorganic metal nanoparticles, clays and so on.METHODS:Many of the recent researches rendered its focus towards the utilization of biopolymer based hydrogel materials for the fabrication of analyte sensors and electrode modifiers owing to their high permeability nature and faster, mobilization of electrons. Such biopolymer hydrogelutilize newer printing methods in electrode prototyping, which renders portable, flexible, and advanced bioelectronics sensor with high performance characteristics. Few researchers have also stated the use of polyaniline reinforced biocomposites for the fabrication of electro-chemical sensors and actuators because of their advantageous properties, which makes them a potential material choice for electronics applications.RESULTS:Nano-particles of polyaniline were proved to improve the detection limit and sensitivity of the sensor even when used for recognizing a single molecules. Bionanocomposites possess excellent thermo-mechanical properties in the designed nanocomposite, even at low nanoparticle concentrations. In fact, these materials have high hardness and stability, giving rise to excellent mechanical characteristics. Furthermore, the incorporation of nanoparticles into a biopolymeric matrix enhanced its electrical conductivity, barrier properties, and consistency. Also, the powerful interaction between biopolymers and functional groups of nanoparticles increased the strength of bio-nanocomposites.CONCLUSION:Nanobiocomposites based biosensors were found to possess high specificity, sensitivity, and wider target spectrum. Current review deals with the use of sustainable and renewable biocomposites for the preparation of biosensors and actuators, their properties like sensitivity, limit of detection, advantages over the synthetic material and environmental hazards.

A Review on Polyaniline: Synthesis, Properties, Nanocomposites, and Electrochemical Applications

The development in the use of polyaniline (PANI) in advanced studies makes us draw attention to the presented research and combine it into one study like this one. The unique composition of PANI qualifies it for use in electrochemical applications in addition to many other applications whose use depends on its mechanical properties. Based on this, it is necessary to limit the reactions that produce PANI and the cheapest cost, and then limit the current uses in the formation of nanocomposites with metals, their oxides, and/or carbon nanocomposites in order to determine what is missing from them and work on it again to expand its chemistry. The development in the use of PANI in advanced studies makes us draw attention to the research presented on PANI and combine it into one study. One of the very important things that made PANI possess a very huge research revolution are preparation in a variety of ways, easy and inexpensive, from which a daily product can be obtained with very high purity, as well as its distinctive properties that made it the focus of researchers in various scientific departments. The unique structure of PANI, which is easy to prepare in its pure form or with various chemical compounds including metals, metal oxides, and carbon nanomaterials (such as carbon nanotubes, graphene, graphene oxide, and reduced graphene oxide), qualifies it for use in electrochemical applications. The various studies reviewed showed that PANI gave good results in the applications of super capacitors. In some of the studies mentioned later, it gave a specific capacitance of 503 F/g, cycle stability 85% at 10,000 cycles, energy density 8.88 kW/kg, and power density 96 W h/kg. It was also noted that these values improved significantly when using PANI with its nanocomposites. Because of its good electrical conductivity and the possibility of preparing it with a high surface area with nanostructures in the form of nanowires, nanofibers, and nanotubes, PANI was used as a gas sensor. We have noticed, through the studies conducted in this field, that the properties of PANI as a basic material in gas sensors are greatly improved when it is prepared in the form of PANI nanocomposites, as explained in detail later. From this review, we tried with great effort to shed light on this attractive polymer in terms of its different preparation methods, its distinctive properties, its nanocomposites, and the type of polymerization used for each nanocomposites, as well as its applications in its pure form or with its nanocomposites in the supercapacitor and gas sensor applications.

Electrochemically Prepared Polyaniline as an Alternative to Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) for Inverted Perovskite Solar Cells

The goal of this work is to substitute the conventional high-cost poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) in inverted perovskite solar cells (PSCs) with an efficient and conducting polyaniline (PANI) polymer. The reported use of PANI in PSCs involves a chemical synthesis method which is prone to contamination with impurities as it requires several materials for polymerization and adhesion improvement with substrates, contributing to low device efficiencies. This work mitigates this issue using an electrochemical method that is low cost, less time consuming, and capable of producing thin films of PANI with excellent adhesion to substrates. Results demonstrated that the power conversion efficiency of the electrochemically synthesized PANI-based PSC is 16.94% versus 15.11% for the PEDOT:PSS-based device. It was observed that the work function of PANI was lower compared to that of PEDOT:PSS which decreased VOC but enhanced hole extraction at the hole transport layer/perovskite interface, thus increasing JSC. Doping electrolyte solution with lithium bis(trifluoromethanesulfonyl)imide LiTFSI increased the work function of PANI, thus increasing VOC from 0.87 to 0.93 V. This method enables simple and scalable synthesis of PANI as a competitive hole transport material to replace rather expensive PEDOT:PSS, thus enabling an important step toward low-cost inverted perovskite photovoltaic devices.

Use of polyaniline coating on magnetic MoO3 and its effects on material stability and visible-light photocatalysis of tetracycline

A semiconducting material (polyaniline-coated magnetic MoO3) with photodegradative properties and low solubility was synthesized and assessed in the degradation of tetracycline (TC) to address the rising concern of antibiotics in water systems. Polyaniline (PANI) provided a protective coating, significantly reducing MoO3 dissolution across a wide pH range, while the Fe3O4 core facilitated photocatalyst extraction from water. Uncoated MoO3@Fe3O4 dissolution significantly increased with increasing pH (dissolved Mo percentage of 2.9% at pH 3 and 22.9% at pH 10). With the PANI coating, dissolution was reduced to 1.6% at pH 3 and 5.6% at pH 10. The TC removal by PANI@MoO3@Fe3O4 was 8.2 mg TC/g photocatalyst in visible light and 6.5 mg/g in dark within 35 min under optimum conditions. The degradative properties of PANI@MoO3@Fe3O4 toward TC were facilitated by reactive species produced from water oxidation by photogenerated holes (h+). This initial assessment of PANI@MoO3@Fe3O4 as a photocatalyst for pharmaceutical contaminant degradation indicates PANI@MoO3@Fe3O4 is a promising material useful for wider environmental applications.

Cr(VI) adsorption by the polyanyline and zeolite/polyaniline–sulphuric acid composite

The adsorption properties of the samples of polyaniline (PAn) and zeolite/polyaniline (Zt/PAn) composite regard to Cr(VI) have been studied. The samples of the PAn and Zt/PAn composite were prepared in the 0.5 M sulfuric acid aqueous solution by oxidative polycondensation of aniline by ammonium peroxydisulfate respectively under the presence and absence of the zeolite powder in the reaction mixture. The molar ratio of aniline to ammonium peroxydisulfate during synthesis was 1 : 1.1, while the weight ratio of aniline to zeolite was equal to 1 : 1. The formation of PAn and Zt/PAn composite was confirmed by X-ray phase analysis, FT-IR spectroscopy, thermogravimetric studies and results of electrical conductivity measurements. Analysis of the spectral, thermal and electrical properties of the synthesized samples of Zt/PAn composites showed their essential differences in relation to individual samples of the zeolite and polyaniline. It was determined that the structure of polyaniline in the synthesized samples of PAn and Zt/PAn is amorphous with insignificant inclusions of polyaniline crystallites (in the form of emeraldine salt of sulfuric acid) deposited on polycrystalline zeolite particles as carrier-matrices. Thermogravimetric studies of PAn samples and Zt/PAn composites confirmed the composition of composites and the dependence of their thermal stability on the content of natural mineral. The defined values of the specific conductivity for the synthesized samples of zeolite/polyaniline composites confirmed the presence of sulfuric acid in the composites. It is determined the availability and high efficiency of the use of PAn and Zt/PAn composites, in which polyaniline is doped by sulfuric acid during synthesis, for Cr(VI) sorption from aqueous solutions. It was demonstrated that Cr(VI) adsorption by produced samples can be described sufficiently good by Langmuir or Freundlich adsorption isotherms, while the kinetics of process is in good agreement with the model of pseudo second order. Keywords : polyaniline, zeolite/polyaniline, properties, adsorption of Cr(VI).

Additive Manufacturing of Polyaniline Electrodes

Since its discovery, polyaniline (PANI) has been a promising material for numerous applications due to its various desirable properties, e.g. tuneable conductivity, high pseudocapacitance or biocompatibility [1]. PANI has been incorporated as a composite for many electrochemical applications, from supercapacitors [2] to sensors [3], but its full potential is still limited by its poor processability as it cannot fully access the benefits of novel fabrication techniques like additive manufacturing (AM). The structural complexity and design flexibility of AM combined with the great properties of PANI would open up new application fields, from energy storage over wearable electronics to conductive implants. However, the non-thermoformable character of PANI limits the use of conventional AM techniques, e.g. Fused Deposition Modelling (FDM), to composites with only low PANI contents [4].Recently developed AM techniques using thermal doping of PANI [5] open up new possibilities for the use of PANI in AM. In this work, a novel process based on the thermal doping of PANI with dodecyl benzene sulfonic acid (DBSA) was used for the printing of electrodes for energy applications. For this, a commercially available FDM printer (Prusa i3 MK3S+) was modified with a 3D printed syringe extrusion system, replacing the regular print head. PANI emeraldine salt was synthesised using chemical oxidation and ultrasound at low temperatures, de-doped and ground to a small particle size. The polymer was then mixed with DBSA in order to obtain a viscous, printable paste. In this process, DBSA acts as both the dispersant and dopant for PANI. Thermal pre-treatment of the paste and the use of the printer hot-bed initiates the doping process, solidifying the paste, which allows for the AM of three dimensional conductive structures. The printing process was characterised and optimised in regards to pre-treatment time and temperature, hot bed temperature as well as nozzle distance from the hot bed. A fully 3D printed capacitor with PANI-DBSA electrodes and a polyvinyl alcohol/sulphuric acid electrolyte gel was fabricated and characterised in order to showcase the potential of this technique for electrochemical applications.[1] Baker, C. O., Huang, X., Nelson, W., Kaner, R. B., Chem Soc Rev 46 2581 (2001).[2]Shen, Y., Qin, Z., Li, T., Zeng, F., Chen, Y., Liu, N., Electrochimica Acta 356 136841 (2020).[3] Bao, Q., Yang, Z., Song, Y., Fan, M., Pan, P., Liu, J., Liao, Z., Wei, J., J. Mater. Sci.: Mater. Electron. 30 1751 (2018).[4] Wibowo, A., Vyas, C., Cooper, G., Qulub, F., Suratman, R., Mahyuddin, A. I., Dirgantara, T., Bartolo, P., Materials 13 512 (2020).[5] Holness, F., Price, A. D., Smart Mater. Struct. 1 015006 (2018).

PVC based flexible nanocomposites with the incorporation of Polyaniline and Barium Hexa-Ferrite nanoparticles for the shielding against EMI, NIR, and thermal imaging cameras

The chemical oxidative method was used for the polymerization of the polyaniline (PANI) by the use of ammonium persulphate as oxidant and formic acid as a dopant. The co-precipitation method was for the precipitation of barium Hexaferrite (BaFe). By the use of polyaniline, polyvinyl chloride, and barium Hexaferrite the magnetic and electrically conductive polymer nanocomposites films were synthesized with a solution casting method having a thickness of 0.5 mm. Enhanced EMI shielding effectiveness was achieved with very less nanocomposite film thickness using novel combination of electrically conductive polymer and ferrite nanoparticles. The effects of synthesis parameters on the features of the subsequent nanocomposites like near-infrared (NIR) transmission, electrical conductivity, tensile strength, and electromagnetic interference (EMI) shielding effectiveness by absorbance and reflection was examined in the frequency region of 0.1–20 GHz. The electrically conductive nanocomposites were characterized by XRD, UV/Vis/NIR spectroscopy, SEM, VNA, 2-Probe Method, and thermal images. The different concentrations of polyaniline and barium Hexaferrite result in different electrical conductivity values, mechanical properties, transmission value, and shielding efficiencies at the 0.1–20 GHz frequency range. The maximum attenuation achieved by PVC/PANI nanocomposites was 43.76 dB while PVC/PANI/BaFe nanocomposites have 78 dB.

In Situ Synthesis of a Polyaniline/ Fe-Ni Codoped Co3O4 Composite for the Electrode Material of Supercapacitors with Improved Cyclic Stability.

Conductive polymers have become a remarkable candidate for electrode materials of supercapacitors. Polyaniline (PANI) is the most promising contender for supercapacitors because of its easy method of synthesis, low cost, and higher choice in the improvement of energy storage applications. The main issue in the use of PANI in supercapacitors is its lower stability. In this work, PANI@Fe–Ni codoped Co3O4 (PANI@FNCO) nanocomposite has been prepared by in situ addition of 10 wt % FNCO as fillers in the PANI matrix. The nanocomposites were then characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry to observe the morphology, crystal structure, functional groups, and thermal stability of samples, respectively. SEM results showed that FNCO was fairly dispersed in the PANI matrix, while XRD results showed a broad peak for nanocomposites because of the semicrystalline nature of polymers. The electrochemical properties of the samples were analyzed via cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy. PANI@FNCO nanowires are found to overcome the shortcomings in electrochemical energy storage devices by exhibiting a higher value of specific capacitance of 1171 F g–1 and energy density of 144 W h kg–1 at a current density of 1 A g–1. Moreover, the FNCO nanowires also showed a cyclic charge/discharge stability of 84% for 2000 cycles.

Effect of a temperature threshold on the electrorheological performance of ionic liquid crystal polyanilines

A series of ionic liquid crystal polyanilines (ILCPs) electrorheological (ER) compounds were synthesized by use of polyaniline, naphthalene disulfonic acid and pyridinyl-containing mesogen. The chemical structure, thermal property, morphology, liquid-crystalline behavior, dielectric property and ER effect of the ILCPs-based ER fluids were characterized by use of various experimental techniques. The synthesized ILCPs displayed nematic liquid-crystalline phase, and the different mesogens played a determinant role in the liquid crystal behavior. The experimental results about dielectric property of the ILCPs suggested that both dielectric constant and dielectric loss increase with raising the temperature, showing a sudden change around glass-transition temperature. The ILCPs-based ER fluids contained an integrated character of liquid crystal, poly(ionic liquid) and polyaniline-base ER suspensions. These characteristics had strong dependence on operating temperature, and a temperature threshold was observed on the ER performance. The shear stress of the ER fluids increased abnormally near glass-transition temperature, which was due to the synergetic effect between the mesogenic orientation and the stretched polyaniline droplets induced by the electric field.

Технология получения нанокомпозитов для сорбционной очистки водных сред

The paper presents a technique for obtaining a universal composite nanomaterial for effective sorption water purification from pollutants of various chemical nature. The proposed material is a nanocomposite based on reduced graphene oxide modified with a functional organic component — polyaniline, which also includes oxidized carbon nanotubes as a structure former. The use of polyaniline makes it possible to significantly increase the activity and sorption capacity of the developed graphene material. The authors were developed a number of nanocomposites, which differ in the final stage of the pre-prepared hydrogel technology: drying in air (drying oven), freeze drying, drying under supercritical conditions (supercritical fluid — isopropyl alcohol). In addition, the effect of carbonization as an additional stage (T = 800 °C, argon) was studied in the article. The materials surface morphology was evaluated using scanning electron microscopy. The specific surface area and the parameters of the porous space were determined by nitrogen adsorption. The materials specific surface area increases depending on the choice of drying technology for the initial hydrogel (drying oven — 80 m2/g → freeze drying — 180 m2/g → supercritical drying — 290 m2/g), and also increases after the carbonization stage and reaches a value of ~ 350 m2/g. The nanocomposites sorption capacity to the organic dyes (methylene blue (MB) and solar yellow (SY)), as well as to heavy metals (for example, zinc ions) was determined. It was found that the value of MB sorption is up 1380 to 1800 mg/g, for SY — up 159 to 300 mg/g, for zinc — up 31 to 230 mg/g. At the same time, the sample processed under supercritical conditions, followed by carbonization, were shown the best characteristics.

Application of polyaniline and polypyrrole in electronics

Aspects of application of nitrogen-containing polyconjugated systems in electronics are considered. It is shown that the use of polyaniline and polypyrrole in the manufacture of structural elements of current sources and supercapacitors has significant prospects for increasing the efficiency of these devices. The fundamental possibility of using polyaniline in the creation of electrochromic displays and photovoltaic cells is shown.

Synthesis, characterizations and application of polyaniline-paint as anticorrosion agent

In this work, we have carried out the synthesis and characterization of paints based on an epoxy resin by using polyaniline as a corrosion inhibitor for protecting the mild steel in an aggressive environment (5% NaCl). We have opted for the formulation of several epoxy paints in aim to their uses as primary layers and to compare their anticorrosion properties for the mild steel protection in saline medium. We used polyaniline and zinc phosphate (proposed by ENAP) as anticorrosion agents. During the synthesis of the paint, we controlled three parameters: density, solid content, and viscosity. Two methods, one experimental and one theoretical, have been implemented to monitor the effectiveness of the formulated. According to the results obtained by the efficiency calculations, it was found that the efficiency increased with the increase of the percentage of PANI. The weight loss method was also used to evaluate corrosion, the value of the protective efficiency reached 97,43% for 8.70 mg of polyaniline. Furthermore, in addition, the morphology of the finished samples was observed using the scanning electron microscopy. Corrosion-resistant paints must have maximum compactness to present a significant barrier effect. The grid tests allow us to evaluate the adherence of the paint and show the good behavior of our product in accelerated corrosive environment and clearly demonstrate that they preserve their adhesion properties. HIGHLIGHTS Use of polyaniline and phosphate zinc (proposed by ENAP) as anticorrosion agents. The inhibition efficacy of the studied coatings realized by two methods, one experimental and the other theoretical. The efficiency increased with the increase of the percentage of PANI. The corrosion inhibition for mild steel was studied using weight loss test and the neutral salt spray test (NSS).

Polyaniline-TiO2-based photocatalysts for dyes degradation

For the last few decades, photocatalysis has attracted as an emerging successful technology for purifying wastewater by dye degradation from households and industries. TiO2-based photocatalysis has gained wide attention due to its importance in energy source as well as its outstanding involvement in the reduction in environmental problems. Consequently, researchers and scientists are looking for the synthesis of polyaniline-TiO2-based photocatalysts which are widely being used for the degradation of dyes. Lately, the use of polyaniline as photosensitizers has proved that it immensely enhances photodegradation by its excellent photocatalytic activity under both ultraviolet light and natural sunlight irradiation. Considering this most unique performance of Polyaniline-TiO2-based photocatalysis, the present review provides the recent advances and trends in the development of ultraviolet and visible light-responsive polyaniline-TiO2-based photocatalysis for their potential application in environmental remediation by dye degradation.

Semiconducting elastomers based on polyaniline/clay nanocomposites and SEBS obtained by an alternative processing technique

The use of Polyaniline (PAni) as conductive filler in several kinds of non-conductive polymers, such as elastomers, has been extensively studied in the production of easily processable semiconductors. This work focuses on the use of a PAni/clay nanocomposite (PCN) – instead of pristine PAni – as conductive filler of styrene-butadiene rubber (SEBS) to produce a PCN/SEBS semiconducting elastomer. In order to accomplish this, a novel solvent-free and low-temperature press-processing technique was proposed and applied. It was also compared to the traditional rubber mechanical processing method.The preparation of PCN/SEBS was conducted by following a two-stage procedure: Pain in situ synthesis and mechanical mixing. PCN/SEBS was characterized by Raman spectroscopy, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM), the electrical properties were measured by means of the two-probe technique and electrochemical impedance spectroscopy (EIS). It was found that the traditional processing method led to a highly insulating material, while the proposed procedure results in semiconducting composites, showing electrical conductivity values up to 10−7 S cm−1.From the mechanical standpoint, this novel treatment results in composites with lower stiffness at low temperatures and similar elastic behavior at the transition region when compared to the material produced by the typical mixing chamber procedure. Although this method still needs to be improved since these materials show less homogeneity than their counterparts and they crumble at ∼100 °C, this work sets the foundation for an alternative processing method to obtain PAni-based semiconducting elastomers.