PANI Chains Research Articles

Comprehensive study of linear and nonlinear optical properties of polyaniline-Al2O3 nanocomposites for optoelectronic applications

This study explores the synthesis of polyaniline-aluminum oxide nanoparticle (PANI-Al₂O₃ NPs) hybrid nanocomposites. An optimized electrochemical polymerization technique was employed to incorporate varying concentrations (5, 10, 15, and 20 wt.%) of Al₂O₃ NPs into the PANI matrix. Comprehensive characterization focused on structural, dielectric, and optical properties, both linear and nonlinear. Williamson-Hall (W-H) analysis revealed average crystallite sizes ranging from 57 nm for pure PANI to 119 nm for 20 wt.% Al₂O₃ nanocomposites. The initial incorporation of a small amount of Al₂O₃ NPs reduced crystallite size, indicating interactions with PANI chains. However, further addition of Al₂O₃ NPs reversed this trend, resulting in increased crystallite size due to NPs aggregation. The Urbach energy, which reflects the width of the tail of localized states in the band gap, increased from 446 meV for pure PANI to 528 meV for 20 wt.% Al₂O₃. Optical bandgap energies showed a slight decrease from 2.56 eV to 2.53 eV for Eg1 and from 3.70 eV to 3.85 eV for Eg2 as Al₂O₃ concentration increased. Furthermore, the plasma frequency resonance (ωₚ) of the materials decreased from 6.68×109 Hz for pure PANI to 3.69×109 Hz for 20 wt.% Al₂O₃, highlighting the impact of Al₂O₃ incorporation on electronic properties. Quantitative evaluation of optical properties revealed substantial improvements. The third-order nonlinear susceptibility (χ³) increased from 2.5 × 10−11 to 7.7 × 10−11 e.s.u. at 15 wt.% Al₂O₃, and the nonlinear refractive index (n₂) increased from 5.8 × 10−10 to 1.9 × 10−9 e.s.u. These findings underscore the potential of Al₂O₃ NPs in enhancing the physical and optical properties of PANI, establishing these nanocomposites as promising candidates for advanced optoelectronic applications.

Microporous Zr-metal-organic frameworks based-nanocomposites for thermoelectric applications

In the area of energy storage and conversion, Metal-Organic Frameworks (MOFs) are receiving more and more attention. They combine organic nature with long-range order and low thermal conductivity, giving them qualities to be potentially attractive for thermoelectric applications. To make the framework electrically conductive so far, thermoelectricity in this class of materials requires infiltration by outside conductive guest molecules. In this study, an in-situ polymerization of conductive polyaniline inside the porous structure of MOF-801 was conducted to synthesize PANi@MOF-801 nanocomposites for thermoelectrical applications. The growth of polyaniline chains of different loadings inside the host MOF matrix generally enhanced bulk electrical conductivity by about 6 orders of magnitude, leading to Seebeck coefficient value of -141 µVK−1 and improved thermal stability. The unusual increase in electrical conductivity was attributed to the formation of highly oriented conductive PANi chains inside the MOF pores, besides host–guest physical interaction, while the Seebeck coefficient enhancement was because of the energy filtering effect of the developed structure. Modulating the composition of PANi@MOF-801 composites by varying the aniline: MOF-801 ratio in the synthesis bath from 2:1 and 1:1 to 1:2 leads to a change in the semiconductor properties from p-type semiconductor to n-type. Among the examined composites with n-type semiconducting properties exhibited the highest ZT value, 0.015, and lowest thermal conductivity, 0.24 Wm−1 K−1. The synthesized composites have better performance than those recently reported for a similar category of thermoelectric materials related to MOF-based composites.

Eco-friendly engineering of micro composite-based hydroxyapatite bio crystal and polyaniline for high removal of OG dye from wastewater: Adsorption mechanism and RSM@BBD optimization

The presence of harmful substances such as dyes in water systems poses a direct threat to the quality of people's lives and other organisms living in the ecosystem. Orange G (OG) is considered a hazardous dye. The existing paper attempts to evaluate a low-cost adsorbent for the effective removal of OG dye. The developed adsorbent Polyaniline@Hydroxyapatite extracted from Cilus Gilberti fish Scale (PANI@FHAP) was elaborated through the application of the in situ chemical polymerization method to incorporate PANI on the surface of naturally extracted hydroxyapatite FHAP. The good synthesis of PANI@FHAP was evaluated through multiple techniques including X-ray diffraction (XRD), Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS), Fourier Transforms Infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) coupled with thermal differential analysis (DTA) analysis. The results reveal a highly ordered disposition of PANI chains on FHAP, resulting in a well-coated FHAP in the PANI matrix. Furthermore, the presence of functional groups on the surface of PANI such as amine (-NH2) and imine (=NH) groups would facilitate the removal of OG dye from contaminated water. The adsorption of OG onto PANI@FHAP was conducted in batch mode and optimized through response surface methodology coupled with box-Behnken design (RSM/BBD) to investigate the effect of time, adsorbent dose, and initial concentration. The outcomes proved that OG adsorption follows a quadratic model (R2 = 0.989). The kinetic study revealed that the adsorption of OG fits the pseudo-second-order model. On the other hand, the isotherm study declared that the Freundlich model is best suited to the description of OG adsorption. For thermodynamic study, the adsorption of OG is spontaneous in nature and exothermic. Furthermore, the regeneration-reusability study indicates that PANI@FHAP could be regenerated and reused up to five successive cycles. Based on the FTIR spectrum of PANI@FHAP after OG adsorption, the mechanism governing OG adsorption is predominantly driven by π-π interaction, electrostatic interaction, and hydrogen bonding interactions. The obtained results suppose that PANI@FHAP adsorbent can be a competitive material in large-scale applications.

Fabrication of a high-performance symmetrical supercapacitor based on electrochemically interconnected Cu:NiO@rGO:PANI/NF electrodes

A three-step electrodeposition synthesis was carried out to prepare a nanocomposite electrode of copper-doped nickel oxide and reduced graphene oxide-doped polyaniline with synergistic effects. Nickel foam was utilized as a current collector. XRD, FTIR and XPS studies confirm the molecular bond formation and molecular phase of the produced materials. According to the EDS results, the rGO:PANI/NF electrode contains 0.29 % nitrogen (N), 17.39 % carbon (C), and 9.81 % oxygen (O), while the Cu:NiO@rGO:PANI/NF electrode contains 8.24 % copper (Cu), 9.22 % carbon (C), 7.21 % oxygen (O), and 0.72 % nitrogen (N). The electrochemical performance of rGO:PANI/NF and Cu:NiO@rGO:PANI/NF electrodes were tested in a three-electrode cell with 3 M KOH aqueous electrolyte. High specific capacitances of 644.5 and 807.1 Fg−1 are achieved with the rGO:PANI/NF and Cu:NiO@rGO:PANI/NF electrodes at a current density of 20 Ag−1, respectively. The Cu:NiO@rGOPANI/NF also has a lower charge transfer resistance (RCT = 0.9 Ω) than the rGO:PANI/NF electrode (RCT = 3.8 Ω). This means NiO plays a crucial role in facilitating the transportation of charges between rGO:PANI. NiO acts as a “superhighway” that enables efficient and speedy charge transport. The expanded BET surface area of Cu:NiO@rGO:PANI/NF can be attributed to a well-interconnected network of PANI chains with NiO. In order to demonstrate a further application, an all-solid-state symmetrical supercapacitor (SSC) was then fabricated using the Cu:NiO@rGO:PANI/NF electrodes. The operating potential range is between 0 and 1.5 V. The device has a good capacitance of 81.9 Fg−1 at 4.5 Ag−1, and a capacitance retention of 97.6 % at a specific current of 10 Ag−1 after 10,000 cycles. The symmetrical device has a maximum energy density of 25.6 Wh kg−1 at a high power density of 1297.6 W kg−1 at 4.5 A g−1. In light of these results, the nanocomposite-based solid-state supercapacitor is considered to be a promising device for the development of high-performance symmetric supercapacitors.

Electrochemical sensors based on polyaniline nanocomposites for detecting Cd(II) in wastewater

A novel imprinted polyaniline-gold nanoparticle (PANI-AuNPs) nanocomposite modified glassy carbon electrode was strategically constructed and systematically explored for sensitive voltammetric quantification of toxic heavy metal Cd(II) in wastewater. Morphological studies revealed uniform dispersion of AuNPs (avg. diameter ∼13 nm) across PANI polymer matrix. Electrochemical testing displayed 320% enhanced oxidation current and 5.7 times higher electron transfer rate constant for Cd(II) relative to bare electrode owing to synergistic effects between highly conductive PANI chains and ultrafine nanosized AuNPs. Exceptionally low 1.2 μg/L limit of detection and wide 5–100 μg/L dynamic linear range was accomplished. The sensor demonstrated commendable accuracy (96–103% recovery) in detecting Cd(II) from spiked industrial effluent and tap water samples. The outstanding sensitivity surpasses previous reports on Cd(II) imprinted sensors. Fundamental mechanistic insights gained on interfacial structure-dynamic relationships can stimulate rational engineering of high-efficiency imprinted nanohybrid materials towards target toxins. This novel PANI-Au electrochemical detector provides a versatile, inexpensive, field-deployable analytical tool for stringent water quality monitoring ensuring food and environmental safety.

3D nanostructured conductive PANI/MXene hydrogels for durable aqueous Zn-ion batteries

PANI/MXene hydrogels show a three-dimensional (3D) network structure of MXene nanosheets interconnected with PANI chains through hydrogen bond interactions, thus greatly improving the electrochemical reactivity and stability.

Engineering energy storage properties of rGO based Fe2O3/CuO/PANI quaternary nanohybrid as an ideal electroactive material for hybrid supercapacitor application

Here, we report the synthesis of novel electrode material rGO@ Fe2O3/CuO/PANI by a facile hydrothermal route. PANI chains are deposited on the rGO@ Fe2O3/CuO by in situ chemical oxidative polymerization route to acquire the quaternary nano composite powders. The nanocomposite active electrode composed of rGO@Fe2O3/CuO/PANI (1%, 3%, 5%) reveals a higher specific capacitance of 1210 Fg−1 and outstanding cycle stability at 1 Ag−1. Electrochemical studies divulge a greatest specific capacitance in 1255 Fg−1 at a sweep rate of 5mVs−1. The ratio of rGO content rises also improve the charge transfer and enhances the redox reactions kinetics according to EIS investigation. Succeeding 1000 cycles of electrochemical testing, the nanohybrid electrode manifesting marvellous cycling stability, diminishes just 4% of its initial capacitance (during the first cycle). To accomplish the outstanding gravimetric capacitance and marvellous cyclic stability, the rGO@ Fe2O3/CuO/PANI nanostructure of the nanohybrid decorated directly on the Nickel Foam whose ion diffusion channel has been reduced and more active sites are brought in to contact with nanocomposite. As a result, fascinating performance of supercapacitor rGO@ Fe2O3/CuO/PANI nanocomposites is deemed as a viable active electrode material for further endows in energy storage device application.

Enhanced photocatalytic performance of PS/F-PANI/PNT films for visible-light-induced hydrogen production

This study aims to develop polystyrene/polyaniline/Pt/N-TiO2 (PS/PANI/PNT) photocatalytic films for hydrogen production under simulated sunlight to improve the efficiency of photocatalyst recycling. The effects of the molar ratio of aniline monomer (AN) to oxidizing reagent (ammonium peroxydisulfate, APS) and the weight ratio of AN to PNT on the conductivity of synthesized nanofiber PANI (F-PANI) materials were investigated. PS/PANI/PNT with F-PANI/PNT were synthesized for photocatalytic hydrogen production. An AN/APS molar ratio of 1:2 in F-PANI/PNT was suitable for AN oxidation. The conductive pathway of PANI chains was enhanced by PNT addition at a AN/PNT weight ratio of 1:0.25, which was favorable for enhancing conductivity, facilitating the faster migration of electron–hole pairs to the photocatalyst surface to improve the hydrogen production rate. The F-PANI/PNT photocatalyst effectively separates its electron–hole pairs and has strong electron reduction and hole oxidation abilities, which is suitable for improving the photocatalytic hydrogen production capacity. The contact angle of PS/F-PANI/PNT-2–0.25 was lower than that of PS/PNT, indicating that the hydrophilicity and active sites of PS/F-PANI/PNT-2–0.25 increased. The optimal photocatalytic hydrogen production of F-PS/PANI/PNT (28,580 μmol h-1 g-1) was reached when the polymerization temperature, AN/APS molar ratio, and AN/PNT weight ratio were 5 °C, 1:2, and 1:0.25, respectively. The PS/F-PANI/PNT film showed excellent recyclability, with comparable photocatalytic activity even after five cycle repetition tests. This approach provides a promising alternative to traditional photocatalytic systems and contribute to a more efficient photocatalyst recycling process.

Semi-Polycrystalline Polyaniline-Activated Carbon Composite for Supercapacitor Application.

We report on the synthesis of activated carbon-semi-polycrystalline polyaniline (SPani-AC) composite material using in-situ oxidative polymerization of aniline on the carbon surface in an aqueous HCl medium at an elevated temperature of 60 °C. The electroactive polymeric composite material exhibits a uniformly distributed spindle-shaped morphology in scanning electron microscopy (SEM) and well-defined crystallographic lattices in the high-resolution transmission electron microscopy (TEM) images. The X-ray diffraction (XRD) spectrum reveals sharp peaks characteristic of crystalline polyaniline. The characteristic chemical properties of polyaniline are recorded using laser Raman spectroscopy. The cyclic voltammetry curves exhibit features of surface-redox pseudocapacitance. The specific capacitance calculated for the material is 507 F g-1 at the scan rate of 10 mV s-1. The symmetrical two-electrodes device exhibits a specific capacitance of 45 F g-1 at a current density of 5 A g-1. The capacitive retention calculated was found to be 96% up to 4500 continuous charge-discharge cycles and observed to be gradually declining at the end of 10,000 cycles. On the other hand, Coulombic efficiency was observed to be retained up to 85% until 4500 continuous charge-discharge cycles which declines up to 72% at the end of 10,000 cycles. The article also presents a detailed description of material synthesis, the formation of polyaniline (Pani) chains, and the role of material architecture in the performance as surface redox supercapacitor electrode.

A Strand Entangled Supramolecular PANI/PAA Hydrogel Enabled Ultra-Stretchable Strain Sensor.

Hydrogel electronics have attracted growing interest for emerging applications in personal healthcare management, human-machine interaction, etc. Herein, a "doping then gelling" strategy to synthesize supramolecular PANI/PAA hydrogel with a specific strand entangled network is proposed, by doping the PANI with acrylic acid (AA) monomers to avoid PANI aggregation. The high-density electrostatic interaction between PAA and PANI chains serves as a dynamic bond to initiate the strand entanglement, enabling PAA/PANI hydrogel with ultra-stretchability (2830%), high breaking strength (120kPa), and rapid self-healing properties. Moreover, the PAA/PANI hydrogel-based sensor with a high strain sensitivity (gauge factor = 12.63), a rapid responding time (222ms), and a robust conductivity-based sensing behavior under cyclic stretching is developed. A set of strain sensing applications to precisely monitor human movements is also demonstrated, indicating a promising application prospect as wearable devices.

Dielectric, electrical, magnetic, and mechanical properties of Ni-Al ferrite/PANI composite films

ABSTRACT The Ni-Al ferrite nanoparticles are synthesized by the flash auto-combustion method, and PANI is synthesized by the situ-chemical oxidative polymerization method. NiAl-ferrite/PANI/ x (PANI) Nanocomposite Films (x = 0.6 and 0.8) were prepared using a solution casting process. The X-ray results of the NiAlxFe2-xO4/PANI composite manifest that the Ni-Al ferrite fully interacted with PANI molecules and the Ni-Al ferrite particles are embedded in the PANI chains from TEM and SEM images. The dielectric parameters ϵ′, ϵ″ and tan δ decreased with the increase in the frequency of the applied field. The modulus M″ spectra of the investigated samples show two relaxation peaks in two frequency regions. In Cole–Cole plot of M′ versus M″, a semicircular trend is observed, i.e. a non-Debye criterion. The presence of PANI in the NiAl0.6Fe1.4O4/PANI composite films reduces the magnetic properties of the composite samples leading to the decrease of saturation magnetization and remanence magnetization.

Brush-like Polyaniline with Optical and Electroactive Properties at Neutral pH and High Temperature.

In this research, a brush-like polyaniline (poly(2-acrylamide-2-methyl-1-propanesulfonate)-g-polyaniline)-b-poly(N-vinylcarbazole) (BL PAni) was developed as a strategy to overcome the limited processability and dedoping above pH 4 of conventional polyaniline (PAni). For the BL PAni synthesis, RAFT polymerization (homopolymer), RAFT-mediated surfactant-free emulsion polymerization (block copolymer), and interfacial oxidative polymerization were applied to graft the PAni chains. NMR and FT-IR spectroscopies were performed to confirm the structural elucidation of the reaction pathways, while the thermal properties were analyzed by TGA and DSC. Notably, the BL PAni presents absorption throughout the visible region and up to the near-infrared, showing dedoping resistance at up to 80 °C and at a neutral pH. The absorption range of the BL PAni, block copolymer, and homopolymer were studied by UV–Vis spectroscopy in solid-state and dispersion/solution, highlighting BL PAni and poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonate)-b-poly(N-vinylcarbazole) (PAAMP-b-PVK) due to the π-stacking between the anilinium and carbazole groups. The cyclic voltammetry confirmed the persistence of electroactivity at a pH near 7.

Homologous Series of Polyaniline Derivatives Block Copolymers with Amphiphilic and Semiconducting Properties.

Semiconducting polymers with amphiphilic properties can play an increasing role in future organic and unimolecular electronic devices, especially due to their excellent processability and ease of self-assembly into thin films, but they could also be used as intermediate layers to improve electron transport in metal-organic junctions. In this work, we synthesized a homologous series of amphiphiles by copolymerization of aniline with aniline-N-propanesulfonic acid. The polymerization was first initiated with aniline, and the latter monomer was added at different time intervals: 2, 10, 20, 30, 40, and 60 min, spaced from the time of initiation. Thus, the poly(aniline-co-aniline-N-propanesulfonic acid) (PANi-co-PANs) homologous series of copolymers obtained had the same length of the water soluble PANs chain, and a variable length of the water insoluble PANi chain. We demonstrated that there is a strong structure–activity relationship in the homologous series of PANi-co-PANs copolymers, evidenced in the tensiometry and wettability studies, as well as in-depth conductivity with frequency and temperature investigations. We observed a gradual change in solubility, interfacial activity, and conductivity in the homologous series of amphiphiles within the boundaries set by the electrically insulating, hydrophilic PANs chain and the semiconducting, hydrophobic PANi chains; representing a viable platform toward designing polymers with tunable conductivity.

Enhanced hydrophobicity and barrier property of anticorrosive coatings with silicified polyaniline filler

Polyaniline has excellent potential in metal surface protection due to oxidation-reduction reversibility. However, the poor dispersity and endurance of polyaniline limit its further application. Herein, trimethylsilyl-substituted polyaniline (PSiAn) was synthesized and characterized by FTIR and SEM-EDS. Results showed that silanes were successfully linked onto the PANI chains. The fabricated filler exhibits high hydrophobicity and good compatibility in the epoxy matrix. Incorporating PSiAn into epoxy coating has a significant influence to the barrier property, effectively reducing the porosity of coating and interrupting the permeation pathway of aggressive substance. The results of electrochemical impedance spectroscopy showed that the |Z|0.01 Hz of PSiAn/epoxy composite coatings still reached 1010 Ω cm2 after 60-day immersion in 3.5 wt% NaCl solution, which was almost three orders higher than that of the pristine coating. XPS and EIS confirmed the formation of dense complex on alloy surface. It turned out that the synergy between impermeability and passivation effect endowed epoxy coating with excellent corrosion resistance. The long-term effectiveness of anti-corrosion epoxy coating was significantly improved, and a novel approach to preparing a highly hydrophobic filler was proposed.

Fe3O4/PANI nanocomposite core-shell structure in epoxy resin matrix for the application as electromagnetic waves absorber

Fe3O4/polyaniline (Fe3O4/PANI) nanocomposite was prepared and used as filler in the preparation of Epoxy (EP) based coatings on Aluminum (Al) substrates for electromagnetic wave absorption application. The Fe3O4 nanoparticles were synthesized by chemical precipitation (1-Fe3O4) and hydrothermal (2-Fe3O4) methods and were used as core followed by the polymerization of aniline as shell layer. The XRD, FT-IR and FE-SEM analysis were confirmed the successful synthesis of Fe3O4 nanoparticles, and preparation of Fe3O4/PANI core-shell nanocomposite. Fe3O4/PANI nanocomposite as well as graphite (G) powder were used as filler in EP matrix for the preparation of Epoxy/Fe3O4/polyaniline/graphite (EP/Fe3O4/PANI/G) composite coating on Al substrates. The electromagnetic wave absorption properties of EP based composite coatings was evaluated by the analysis of reflection loss (RL) and loss factors against the Fe3O4 synthesis method, Fe3O4/PANI percentage and coating thickness on Al substrates. The refractive index of Epoxy/chemical precipitation Fe3O4/polyaniline/graphite (EP/1-Fe3O4/PANI/G) and Epoxy/hydrothermal Fe3O4/polyaniline/graphite (EP/2-Fe3O4/PANI/G) nanocomposites coatings on Al substrates was measured. The maximum RL values of respectively −34.28 dB and −31.1 dB at 11.2 GHz and 11 GHz frequencies were obtained for EP/1-Fe3O4/PANI/G and EP/2-Fe3O4/PANI/G coatings respectively with the coating thickness of 2 mm. Results showed that the simultaneous presence of superparamagnetic Fe3O4 nanoparticles as well as PANI chains and graphite powder with dielectric properties achieved synergetic and complementary effects on the electromagnetic interference (EMI) absorption properties of EP based composite coatings.

Evaluation of adsorption and biological activities of polyaniline-grafted-pectin as conductive nanogels

Nanogel composites based on hydrolyzed pectin-grafted-polyaniline (HPEc-g-PANi) (GCP) were synthesized via chemical polymerization method and characterized via different analyses including FTIR, 1HNMR, UV-Vis, Raman, XRD, SEM, AFM, TGA, DSC and DMTA. Swelling, electrical conductivity and zeta potential studies were performed to evaluate physicochemical properties. The adsorption studies on GCP for different metal ions of Pb+2, Cu+2, Ni+2 and Cd+2 showed selectivity of GCP toward Pb+2 and high removal efficiency up to 90% by 0.03 g adsorbent for 2 h at pH:5. For determination of hydrophilicity, contact angle measurements were done on PANi and copolymers. HPEc-g-PANi (2:1) copolymer showed more hydrophobicity feature due to lower polar PANi sites which reduces water absorption. Antibacterial analyses demonstrated a desirable inhibition zone of the copolymers and specially PANi. Among copolymers, HPEc-g-PANi (2:1) due to more hydrophobicity represented better antibacterial activity than others. This conclusion support influence of hydrophobicity on antibacterial activity. HPEc macromolecules help to the entrance of PANi chains into bacteria cell wall and destruction of cell cytoplasm. Anticancer experiments indicated an efficient toxicity effect on cancer cells up to 56% reduction in cell viability percentage. Antioxidant test indicated an efficiency inhibition of GCP to free radicals up to a maximum absorption of 80%.

Improved electrochemical performance of symmetric polyaniline/activated carbon hybrid for high supercapacitance: Comparison with indirect capacitance

AbstractPolyaniline (PANI) chains doped with very small amount of Activated Carbon (AC) as an electrode material in aqueous H2SO4 electrolyte was successfully employed in this work to enhance the electrochemical capacitive properties of PANI. The aim of this research is to improve overall specific capacitance of PANI by incorporating only minute amount of AC as a PANI dopant. There are many reports available on PANI/AC but the use of such a minute amount of AC in H2SO4 electrolyte which enhances the overall specific capacity of the composite has not been reported elsewhere. An improvement in the specific capacitance from 763.44 to 897.50 F g−1 in aqueous 0.1 M H2SO4 electrolyte solution is observed by adding mere 0.04 g of AC. It is envisaged that AC enhances SO4−2 ion transportation, forwards a stable and fast surface redox reactions, hence collectively improving the overall capacitive performance of supercapacitor electrode. The charge/discharge measurements shows that AC particles stops the PANI chains degradation during charge/discharge cycle. Also, the retention rate (54%) of PANI1.0/AC0.04 indicates approximately 11% more stability than pure PANI (43%) electrode alone. It was further observed that the electrochemical impedance parameters viz., that charge transfer resistance (Rct) (0.79 Ω), response frequency (0.26 Hz), response time (3.84 s) and knee frequency (9.16 Hz) of PANI1.0/AC0.04 electrode material shows excellent performance of the PANI doped AC. Considering its high specific capacitance, low‐cost and ease of synthesis, PANI1.0/AC0.04 seems to be a promising electrode material for next generation symmetric supercapacitors.

NH3 Sensor Based on rGO-PANI Composite with Improved Sensitivity.

This work reports on a reduced graphene oxide and poly(aniline) composite (rGO-PANI), with rGO clusters inserted between PANI chains. These clusters were formed due the plasticizing effect of N-methyl-2-pyrrolidone (NMP) solvent, which was added during the synthesis. Further, this composite was processed as thin film onto an interdigitated electrode array and used as the sensitive layer for ammonia gas, presenting sensitivity of 250% at 100 ppm, a response time of 97 s, and a lowest detection limit of 5 ppm. The PANI deprotonation process, upon exposure to NH3, rGO, also contributed by improving the sensitivity due its higher surface area and the presence of carboxylic acids. This allowed for the interaction between the hydrogen of NH3 (nucleophilic character) and the -COOH groups (electrophilic character) from the rGO surface, thereby introducing a promising sensing composite for amine-based gases.

Synthesis of polyaniline nanotubes decorated with graphene quantum dots: Structural & electrochemical studies

The aim of this paper was to synthesize sulfonated polyaniline nanotubes (s-PANI-NTs) decorated with graphene quantum dots (GQDs) and explore their use as an electrode material in supercapacitors. Spectroscopic (FTIR, Raman, UV–vis, XPS) studies confirmed the presence of both components in the composite, while microscopic (SEM, TEM) analysis proved that the tubular morphological form of PANI was obtained. Moreover, TEM images showed that the decoration of the s-PANI-NT surface with GQDs resulted in the smoothing of the outer part of the polymer wall. Consequently, a higher dispersibility of the s-PANI-NTs/GQDs composite was achieved. A theoretical investigation of the interactions between PANI chains and GQDs was also performed. Furthermore, voltammetric and impedance spectroscopy studies showed that, in the selected concentration range, modification of s-PANI-NTs with GQDs improved the electrochemical properties of the synthesized material. The large BET specific surface area (44.5 m²⋅g−1) and high specific capacitance (245 F⋅g−1) calculated for the optimal s-PANI-NTs/GQDs composite confirmed that the obtained material can be applied in energy storage systems.

Facile and eco-friendly synthesis of polyaniline/ZnO composites for corrosion protection of AA-2024 aluminium alloy

In this study, organic/inorganic PANI/ZnO composites with different weight proportions were prepared via a simple and environmentally friendly method consisting of ultrasonication and a solution combustion method using urea as fuel. Powder X-ray diffraction and EDAX were carried out to investigate the structure, crystallinity and chemical composition of the samples. Raman spectra were recorded to provide information about the interactions between PANI chains and ZnO. The grain size and morphology were evaluated by laser granulometry. The anti-corrosion properties of ZnO/PANI composites were evaluated for AA-2024 substrates after coating using the drop-deposition technique and ( N -methylpyrrolidone) (NMP) as the solvent. The composite coating was almost stable over a period of 30 days when exposed to an aqueous solution of 3.5% NaCl, as determined by the gravimetric method. The contact angle technique was used to measure the hydrophobicity, which increased to 85° for the coated composite substrate. The potentiodynamic curves showed considerable improvement in the corrosion resistance with increasing ZnO content, and 60 wt% ZnO/PANI resulted in the lowest i corr value with a protection efficiency of 99.99.