PANI Matrix 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.

Impact of varying magnetite nanoparticle concentrations on the structural, electrical, and magnetic properties of polyaniline-based magnetic nanocomposites

We report the synthesis of polyaniline/magnetite nanocomposites (PMNCs) via in situ chemical oxidation polymerization of aniline with magnetite nanoparticles (MNPs) at 5, 12, and 25 wt%. The objective was to evaluate how the MNPs’ proportion affects the electrical, magnetic, and structural properties, which were investigated using XRD, EDXRF, TEM, EIS, ESR spectroscopy, Mössbauer spectroscopy, and VSM. EDXRF confirmed the formation of MNPs, while XRD revealed the crystalline nature of MNPs and the semicrystalline structure of PANI, with a decrease crystallinity index as the MNPs percentage increased. TEM showed PANI encapsulating MNPs with average diameters of 9.7 ± 2, 9.9 ± 2, and 13.1 ± 3 nm for PMNC25, PMNC12, and PMNC5, respectively. Conductivity values of PANI, PMNC25, PMNC12 and PMNC5 were 7.96 ×10⁻⁴, 1.38 ×10⁻⁴, 2.19 ×10⁻⁴ and 2.31 ×10⁻⁴ S/cm, respectively. ESR indicated cationic radicals responsible for conductivity. Saturation magnetization (Ms) for MNPs, PMNC25, PMNC12 and PMNC5 were 93.4, 24.6, 11.8 and 5.6 emu/g, respectively, with superparamagnetic behavior observed. Our findings show that incorporating MNPs into the PANI matrix modulates electrical conductivity and magnetic properties while maintaining the nanocomposite’s structure, highlighting the multifunctional potential of these composites.

Linear and nonlinear optical properties of hybrid Polyaniline/CoFe2O4 nanocomposites: Electrochemical synthesis, characterization, and analysis

This study presents a focused investigation and comprehensive analysis of the synthesis of hybrid Polyaniline/Cobalt ferrite (PANI/CoFe2O4) nanocomposites using an optimized electrochemical polymerization method. CoFe2O4 nanoparticles (NPs) were incorporated into the PANI matrix at varying concentrations (3, 6, and 12 wt%). The research examined the newly synthesized hybrid nanocomposites in terms of their structure, dielectric properties, and both linear and nonlinear optical properties. As a result of the Williamson-Hall method, the average crystallite size varied between 45 and 99 nm. Initially, adding a small quantity of NPs decreased the nanocomposite size, but further additions increased it due to aggregation. The Tauc plot showed a gradual increase in the energy band gap of the films as the concentration of CoFe2O4 NPs increased up to 12 wt%. This trend showed stronger absorption bands and higher coefficients, indicating improved light absorption compared to pure PANI films. Dielectric properties, including dielectric constants (ɛr, ɛi) and dielectric loss (tan δ), were examined as a function of frequency. The experimental results indicated that PANI/CoFe2O4 exhibited lower dielectric constants than bare PANI. Concentration-dependent optical properties, such as electronic transition excitation energies, dispersion energies, and optical conductivity, were also investigated. These properties were modeled using a single oscillator based on the Wemple-DiDomenico (WDD) approach. The study revealed a reduction in key optical parameters—linear susceptibility, nonlinear third-order susceptibility, and nonlinear refractive index—as nanoparticle content increased. Conversely, increasing concentrations of CoFe2O4 NPs led to a significant increase in the ratio of free carriers to effective mass (N/m٭), from 3.89 × 10³⁶ to 4.04 × 10³⁶ m⁻³ kg⁻1. Additionally, the electrical conductivity of both PANI and PANI/CoFe2O4 nanocomposites exhibited temperature-dependent improvement, reaching maximum values. The observed findings indicate that hybrid PANI-CoFe2O4 nanocomposites possess enhanced properties, highlighting their promising potential as active materials for a broad range of optoelectronic applications.

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.

Synergistic effect of gold nanoparticles decorated functionalized carbon nanotubes nanohybrids on the thermal, dielectric, and sensing properties of polyaniline ternary nanocomposites

AbstractThe synthesis of gold nanoparticles reinforced functionalized single‐walled/multi‐walled carbon nanotubes nanohybrid based polyaniline nanocomposites were carried out using in situ polymerization. The chemical interaction and nanostructured morphology of the synthesized nanocomposites are studied using ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction analysis, x‐ray photoelectron spectroscopy, and field emission scanning electron microscopy. Thermal stability of synthesized PANI/Au@f‐SWNTs is boosted by a magnitude of 30°C as compared with the pristine PANI matrix, which is attributed to a strong barrier effect because of the development of tortuous path that resulted from a uniform distribution of Au@f‐CNTs throughout the PANI matrix. For PANI/Au@f‐SWNTs, the AC conductivity and dielectric permittivity are improved by a value of 83.58 S/cm and 1.35 × 10−5 as well as the dielectric loss is reduced by a factor of 0.11 in comparison with the pure PANI matrix at an applied frequency of 106 Hz. PANI/Au@f‐SWNTs and PANI/Au@f‐MWNTs ternary nanocomposites exhibited excellent selectivity toward the hazardous Cr(VI) heavy metal ions in an aqueous medium with a limit of detection of 0.74 and 0.89 μM with a binding constant of 1.028 × 105 and 3.46 × 104 M−1, respectively, that can be selective and sensitive for the detection of Cr(VI) metal ions in water at trace level.

Meta-Analysis of the Effect of Inorganic Micro/Nanomaterial Additives on Polyaniline Based NH<sub>3</sub> Gas Sensor Performance

Nowadays conducting polymer based nanocomposites become promising materials for various field of applications like energy harvesting, electronics, and gas sensing devices. This work focuses on the meta-analysis of the effect of different inorganic micro/nano-material additives on polyaniline (PAni) based nanocomposite for ammonia (NH3) gas sensor application at room temperature. The considered NH3 sensors performance parameters are sensitivity, limit of detection (LOD), response time, and recovery time. These parameters show a significant change when inorganic materials like graphene, metal oxides and ternary hybrid materials are mixed with PAni as compared to pure PAni due to the synergetic effect of the micro/nano hybrid combination. The changes in the sensitivity, LOD, response time, and recovery time are elaborated by considering different inorganic micro/nano-material additives in PAni in the framework of pure PAni as a reference point. It is found from analysis that a micro/nano additive in the PAni matrix serve as catalyst and create more active sites in the system, which improves the sensitivity in the range of 23-130 times and LOD is highly reduced by 10-1 to 10-3 order when compared with the sensitivity and LOD of pure PAni. Hence these additives in PAni-based nanocomposite are very crucial and make nanocomposite cost-effective compared to conventional NH3 gas sensors while working at room temperature.

Synthesized PANI/CeO2 Nanocomposite Films for Enhanced Anti-Corrosion Performance.

This study introduces a novel nanocomposite coating composed of PANI/CeO2 nanocomposite films, aimed at addressing corrosion protection needs. Analysis through FTIR spectra and XRD patterns confirms the successful formation of the nanocomposite films. Notably, the PANI/CeO2 nanocomposite films exhibit a hydrophilic nature. The bandgap energy of the PANI composite film is measured to be 3.74 eV, while the introduction of CeO2 NPs into the PANI matrix reduces the bandgap energy to 3.67 eV. Furthermore, the electrical conductivity of the PANI composite film is observed to be 0.40 S·cm-1, with the incorporation of CeO2 NPs leading to an increase in electrical conductivity to 1.07 S·cm-1. To evaluate its efficacy, electrochemical measurements were conducted to assess the corrosion protection performance. Results indicate a high protection efficiency of 92.25% for the PANI/CeO2 nanocomposite film.

Synthesis, characterization, and biosensing performance of cobalt sulphide reinforced polyaniline composites

In this work, the CoS was synthesized by the solvothermal method. The PANI and PANI-CoS composites (1, 5, and 15 wt % CoS in the PANI matrix) were synthesized by the oxidative polymerization method. The PXRD pattern confirmed CoS and PANI peaks matched with JCPDS cards. CoS was successfully embedded in the PANI matrix. The surface morphology of the CoS microspheres are flower-like and shows crossed nanoflakes with a thickness of around 40 nm. These CoS microspheres are transformed into nanoparticles by the presence of PANI. The Nickel Foam/Polymer Composites/GOx were prepared by drop-coating the PEG water-dispersed PCs-modified nickel foam electrode and immobilized with the enzyme glucose oxidase. The CV studies were carried out for three-electrode systems. The sensitivity of PCs toward different concentrations of glucose ranging from 1 mM to 1000 mM was evaluated. Also the enzymatic reaction evaluated by Michaelis-Menten kinetic exhibits a high affinity of GOx to glucose.

Adsorption and supercapacitor applications of CoO-zeolite decorated conducting polymer nanocomposite

ABSTRACT Cobalt Oxide−Zeolite reinforced conducting polymer matrices (PAni@CoO−ZT) were prepared by in-situ oxidative polymerisation, and the samples were characterised by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), UV-visible, scanning electron microscopy (SEM) and Brunauer – Emmett – Teller (BET) techniques, the optical band gap was also evaluated. Moreover, the synthesis and exploration of electrodes are increasingly being considered for the development of conducting polymer-based supercapacitors, which has attracted significant interest in energy conversion and storage technology. Here, hybrid materials applied in the elaboration of the electrodes on the capacitive properties were studied. Therewith, electrochemical measurements revealed that the PAni@CoO−ZT (1:1) and PAni@CoO−ZT (2:1) electrodes had high capacitance of 1069 F·g−1 and 1282 F·g−1 at a current density of 1.0 A·g−1 and outstanding capacitance retention (81.7% and 89.1%) over 1500 cycles, respectively. Generally, producing a PAni matrix on CoO−ZT presented a simple and viable way to ameliorate the capacitive performances of supercapacitor. Furthermore, adsorptive removal of methyl violet (MV) dye by PAni@CoO−ZT adsorbents could be described by the pseudo-first-order and Temkin models. The maximum adsorptive capacity of MV dye by PAni@CoO−ZT (1:1) and PAni@CoO−ZT (2:1) was 74.6 mg·g−1 and 109.8 mg·g−1, respectively.

An in vitro cytotoxicity study on PANI/ZnO nanocomposites against HCT- 116 cancer cells using MTT assay

Polyaniline/ZnO nanocomposites were synthesized with different weight percentage of ZnO (20%, 40%, 60%, and 80%) using an in situ chemical polymerization method. The prepared composite samples were characterized by FT-IR, XRD, TEM, SEM with EDAX, UV-Vis, PL, electrical conductivity, photocatalytic properties, antibacterial and anticancer activity. The presence of functional groups in PANI-ZnO NCs is identified by FTIR spectral analysis. X-ray diffraction patterns show that the nanocomposites exhibit preferential orientational growth along the (002) plane with a hexagonal wurtzite structure. The intensity of the maximum reflection (101) increases with increasing ZnO doping concentrations. The TEM analysis indicates that the spherical shape,the particle size was found to be 36.8 nm. SAED pattern closely matched the peaks of the XRD pattern, confirming that the relevant SAED patterns correspond to hexagonal Wurtzite crystals of ZnO. SEM image shows a spherical morphology and ZnO nanoparticles are homogeniously mixed with PANI matrix. EDAX analysis showed the presence of Zn, C and O.UV-vis absorption spectra reveals increasing wavelength leads to the redshift in which there is a strong interaction between PANI and PANI/ZnO. The band gap energy of PANI/ZnO NCs is decreased to 1.30 eV by adding different concentrations of ZnO. PL analysis showed that the addition of ZnO dopants reduced the bandgap and increased oxygen defect vacancies of PANI/ZnO composites. An increase in ZnO content in the PANI matrix was also seen to cause a decrease in electrical conductivity. This alteration might be connected to ZnO’s doping and dedoping activity in the PANI matrix. Photocatalytic activity of 80 wt%ZnO-doped PANI-NPs through the degradation of methylene blue (MB) pigment studied under UV-A light and had detected 95% of degradation throughout 260 min. The lowest bandgap of 80 wt% ZnO shows the highest photocatalytic MB degradation performance. PANI/ZnO nanocomposite with high concentration of ZnO had good antibacterial activity against both P. aeruginosa and S. aureus. An in vitro study was used to evaluate the cytotoxic effects of PANI and PANI/ZnO NPs on the HCT-116 cell line. The results of the MTT test reveal that PANI/ZnO NPs have a significantly greater cytotoxic effect on the HCT-116 cell line than PANI.

Ag/Cu doped polyaniline hybrid nanocomposite-based novel gas sensor for enhanced ammonia gas sensing performance at room temperature.

Hybrid nanocomposites, which comprise organic and inorganic materials, have gained increasing attention in applications for enhanced sensing response to both reducing and oxidation gases. In this study, a novel nanocomposite is synthesized using chemical polymerization by reinforcing Ag/Cu nanoparticles with different concentrations doped into the polyaniline matrix. This hybrid nanocomposite is used as a sensing platform for ammonia detection with different concentrations (ppm). The homogeneous distribution of Ag/Cu nanoparticles onto the PANI matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of the PANI@Ag/Cu matrix is responsible for the outstanding conductivity, compatibility, and catalytic ability of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were examined using X-ray diffraction, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, energy dispersive spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results indicated that the resistive sensor based on the PANI@Ag/Cu3 hybrid nanocomposite exhibited the highest response toward ammonia at room temperature, with a response value of 86% to a concentration of 300 ppm. We also investigated the sensing properties of volatile organic compounds, including carbon dioxide, carbon monoxide, ethanol and hydrogen sulphide. Characterization and gas sensing measurements exhibited protonation and deprotonation of the PANI@Ag/Cu heterojunction, which contributes to the ammonia sensing mechanism. Overall, the obtained findings demonstrated that the PANI@Ag/Cu hybrid nanocomposite is a promising material for gas sensing applications in environmental monitoring.

Boosting the hydrophobicity of eco‐friendly polyaniline coating using TiO2 and ZnO nanoparticles

This article clarifies the thin layer deposition of superhydrophobic coating using eco‐friendly polymer (polyaniline [PANI]) incorporated with TiO2 and ZnO nanoparticles on indium tin oxide substrate. Using the cyclic voltammetry method, in situ polymerization of PANI incorporated with hybrid (TiO2–ZnO) was accomplished. The morphology and hydrophobicity of electro‐deposited films were examined; the impact of deposition cycles was also investigated. The morphological structure was studied using field‐emission scanning electron microscopy and high‐resolution transmission electron microscopy. X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis proved the incorporation of nanoparticles into the composite matrix. Additionally, the water contact angle of the PANI composite was found to be 150.4°, and the findings reflected that (TiO2–ZnO) nanoparticles were significantly implicated in enhancing this superhydrophobicity. The surface roughness of the PANI matrix was increased when TiO2 and ZnO are added, as was shown by atomic force microscope investigation.

Polyaniline Composites Containing Eco-Friendly Biomass Carbon from Agricultural-Waste Coconut Husk for Enhancing Gas Sensor Performance in Hydrogen Sulfide Detection.

Hydrogen sulfide, a colorless, flammable gas with a distinct rotten egg odor, poses severe health risks in industrial settings. Sensing hydrogen sulfide is crucial for safeguarding worker safety and preventing potential accidents. This study investigated the gas-sensing performance of an electroactive polymer (i.e., polyaniline, PANI) and its composites with active carbon (AC) (i.e., PANI-AC1 and PANI-AC3) toward H2S at room temperature. PANI-AC composites-coated IDE gas sensors were fabricated and their capability of detecting H2S at concentrations ranging from 1 ppm to 30 ppm was tested. The superior gas-sensing performance of the PANI-AC composites can be attributed to the increased surface area of the materials, which provided increased active sites for doping processes and enhanced the sensing capability of the composites. Specifically, the incorporation of AC in the PANI matrix resulted in a substantial improvement in the doping process, which led to stronger gas-sensing responses with higher repeatability and higher stability toward H2S compared to the neat PANI-coated IDE sensor. Furthermore, the as-prepared IDE gas sensor exhibited the best sensing response toward H2S at 60% RH. The use of agricultural-waste coconut husk for the synthesis of these high-performance gas-sensing materials promotes sustainable and eco-friendly practices while improving the detection and monitoring of H2S gas in industrial settings.

Building nickel tungstate nanospheres anchored polyaniline conductive matrixes for trace level electrochemical determination of theobromine in food samples

In this work, a nickel tungstate nanospheres-anchored polyaniline nanocomposite (NiWO4/PANI) was prepared by using a hydrothermal route followed by a chemical oxidative polymerization route and explored as an electrode material for the determination of theobromine (TB). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirm the structural-compositional details of NiWO4/PANI nanocomposite. Further, the successful fabrication of NiWO4 nanospheres perfectly anchoring on the conductive matrix of PANI is revealed by transmission electron microscope (TEM) analysis. The N2 adsorption-desorption isotherm analysis revealed the specific surface area of the composite is 28.49 m2/g. Due to the feasible multiple electroactive sites and the synergistic effect between NiWO4 and conductive PANI matrix in the NiWO4/PANI nanocomposite, it enables rapid electron migration and possesses high electrical conductivity during the sensing performances. From the amperometric i-t method, NiWO4/PANI sensor exhibits a wide linear range (0.05–1350.6 μM) and a low detection limit (0.0079 µM). Besides, NiWO4/PANI based sensor shows excellent stability, anti-interference ability and reproducibility, suggesting NiWO4/PANI composite-modified sensors could be a potential candidate for determining TB in food samples with suitable recovery ranges.

Swift heavy ion irradiation of polyaniline-graphene nanocomposite films: Structural and optical properties

In this study, we investigate the use of swift heavy ions to modify the structural and optical properties of PANI-graphene nanocomposite (PANI-G NC) films. PANI-G NC films were synthesized on Indium Tin Oxide (ITO)-coated glass by electrochemical polymerization of aniline in the presence of CVD-grown graphene. The films were then irradiated with 36 MeV Cu8+ ions at fluences between 5.4 × 1012 and 6.4 × 1013 ions/cm2. SEM results show that irradiation up to 1.6 × 1013 ions/cm2 leads to the formation of a porous interconnected network, with graphene nanoparticles adhering to the PANI matrix. Beyond this fluence, a dense and compact granular structure appears. Raman spectroscopy reveals enhanced Raman scattering of the polaronic lattice and the introduction of defects in graphene. At fluences exceeding 2.1 × 1013 ions/cm2, the obtained spectra reveal a distinctive broad envelope centered at the D and G positions of graphene, characteristic of nanocrystalline graphite. X-ray diffraction shows an increase in both crystallinity and crystallite size of the PANI-G NC film with increasing fluence, followed by a decrease beyond a critical ion fluence. Optical modifications were characterized by a red shift in the UV–Vis spectrum with increased fluence. The optical band gap shows a decreasing trend with ion dose, attributed to the formation of carbonaceous clusters along the latent tracks of energetic ions. In short, this study demonstrates that swift heavy ion irradiation could be an effective tool for enhancing the structural and optical properties of PANI-G NC films and tailoring them for specific applications.

Dielectric and Humidity Sensing Properties in Iron Nanoparticle Substituted Polyaniline Composite

The existence of graphene-based Polyaniline nanocomposite has been demonstrated to be exceptional host matrices for entrapping nano-sized particles, and its composites are widely used in a variety of applications such as transducers, sensors, electrodes, microwave absorption, and thermoelectric applications. The purpose of this study is to investigate the dielectric properties and humidity sensing response of a Fe doped PANI/Graphene (PAFG) composite synthesized in-situ polymerization using adhathoda vasica plant extract. The FT-IR, XRD, and SEM-EDX techniques were used to characterize the sample. The dielectric measurements were performed at 298K over a wide frequency range 5x101 to 5x106 Hz. Humidity response studies were performed at room temperature. Iron nanoparticles distributed homogeneously in the PANI matrix were ascertained from IR spectral data. At room temperature, the dielectric properties of the synthesized DS-4 powder outperform those of the synthesized pristine PANI and Fe nanoparticles, with superior dielectric constant and high dielectric loss. When the synthesized iron decorated composite was exposed between 10% and 97% RH, the electrical resistance decreased, which is attributed to the polarization process affecting electrical conductivity within these materials. The PAFG-40% composite exhibited high sensitivity at low humidity levels ranging from 30% to 70% RH.

High-performance H2 sensor based on Polyaniline-WO3 nanocomposite for portable batteries and breathomics-diagnosis of irritable bowel syndrome

Low-trace airborne hydrogen (H2) detection at room temperature is a prerequisite in designing sensors for portable batteries and breathomics-based diagnosis of human diseases/disorders. The state-of-the-art H2 sensor engineering is concerned with developing organic-inorganic nanocomposites with controlled morphology and enhanced physicochemical attributes. This unprecedented study reports a chemo-resistive-module H2 sensor based on polyaniline-tungsten oxide (PAni-WO3) nanocomposite fabricated through a facile and economic one-pot polymerization route. The morphological and structural analysis revealed the formation of nanocomposite consisting of WO3 nanorods (∼100 nm diameter) dispersed in the PAni matrix consists of particles with size around 200 nm. The PAni-WO3 chemiresistor exhibited a 5-fold enhanced performance towards one ppm of H2 at room temperature compared to pristine WO3 nanorods/PAni. It demonstrated high performance for room temperature H2 detection in terms of low detection limit (1 ppm), high sensitivity, prompt response, fast recovery, and high repeatability. Besides, the fabricated sensor is highly selective and stable for H2 monitoring in capricious environmental conditions (in varying humidity, temperature and interfering analytes). The well-engineered nanocomposite system possessing rational morphology has latent for real-time monitoring of low-trace human breath-borne H2 for non-invasive irritable bowel syndrome (IBS) diagnosis and for sensing leaks in portable batteries, hydrogen production and storage industries, and environmental monitoring.

Enhanced dielectric and photocatalytic properties of TiO2-decorated rGO/PANI hybrid composites synthesized by in-situ chemical oxidation polymerization route

In this research, we synthesized composites of TiO2-decorated rGO surface, encapsulated in PANI matrix by using a facile in-situ chemical oxidation polymerization route. Different nanocomposites are prepared by varying concentration of rGO from 0.1 to 0.7% to PANI/TiO2 hybrid. The resulting composites were characterized by fourier transform infrared (FT-IR) spectroscopy, X-rat diffraction (XRD) analysis, Scanning electron microscopty (SEM), thermogravimetric analysis (TGA) and UV–visible spectroscopy. FT-IR and XRD analysis shows no change in the structure of any composite components and all the three phases retain their structure in the composite. But the dielectric properties of the material enhanced with the gradual increase in dielectric constant with the increase in concentration of rGO in the PANI/TiO2 matrix. The percolation threshold for dielectric constant was found to be 0.7 % rGO contents in PANI/TiO2 hybrid composite and is explained by the Maxwell-Wagner model. Further, this novel composite also presents enhanced photocatalytic properties with the remarkable red shift in the ability of visible light absorption and a narrow band gap in comparison to TiO2. Its hydrogen production ability by water splitting under irradiation is also investigated. The results show low electron-hole pair recombination property of the composite material by the much higher hydrogen production with excellent stability value of the critical composite in comparison to TiO2. Thus, this synthetic strategy provides a scalable approach to enhance the dielectric as well as the photocatalytic properties of the polymer-based inorganic composite for their application in flexible electrical appliances and energy devices.

Electromagnetic attenuation displayed by La-Co substituted Ba-Sr hexaferrite nanoparticles and multiwall carbon nanotubes in polyaniline and polythiophene matrix

Our presented research aims to provide a systematic study of electrical, magnetic and microwave absorption properties of La-Co substituted Ba-Sr hexaferrite nanoparticles and MWCNTs, encapsulated in conductive polymer matrix. La-Co substituted Ba-Sr hexaferrite nanoparticles were produced using Sol-Gel auto combustion, whereas carrier fluid ultrasonication dispersion and in-situ polymerization were used to synthesize their composites with multiwall carbon nanotubes (MWCNTs) and conductive polymers. Structural investigations were accomplished using X-rays diffraction, secondary electron microscopy, Infrared and Raman Spectroscopy. The dielectric measurements revealed increased dielectric losses (4.86 at 1 GHz for pure nanoparticles, which increases up to 11.59 and 13.36 for ternary composites within PANI and PTh matrix), indicating good energy dissipation behavior. The decrease in magnetism was observed due to the weakening of exchange coupling or domain wall pinning at the interface of Ferrite-MWCNTs and Ferrite-Polymer, resulting in lowered saturation magnetization, remanence and coercivity values. The microwave absorption of our samples was evaluated as a function of frequency and thickness, revealing its dependence on the quarter wavelength phenomenon with maximum reflection loss of − 40.4 dB observed for ternary composite with Polythiophene matrix at 7.54 GHz resonance frequency. The dependence of reflection loss peaks on matching thickness was analyzed using calculated thickness profiles, revealing their close agreement with simulated thickness. The study highlighted the potential of synthesized samples for electromagnetic signature reduction, in both commercial and military applications. The resonance bands were found to coincide with the operating frequency of military radars for shipborne and airborne surveillance and navigation in the X band (8–12 GHz).

Conducting polymer encrusted Cu/Mn-MOF-CNDs: A facile synthesis, characterization and its hydrogen evolution activity in alkaline media and seawater

The Composites of polyaniline-bimetallic metal-organic framework with carbon nanodots (PANI/bi-MOF@CNDs) were fabricated by chemically oxidising aniline monomer for the hydrogen evolution process (HER). In this investigation, the composite structure, topography, and characteristics were analysed. The Fourier transform infrared spectroscopy analyses found evidence of electrostatic interaction between the CNDs@MOF and the backbone of the PANI matrix. Investigations using scanning electron microscopy and transmission electron microscopy showed that the CNDs@MOF exhibited uneven crystals with an additional enveloping PANI material. In an alkaline medium, the produced PANI composite (PANI/bi-MOF@CNDs) electrocatalyst showed a small overpotential and significant Tafel slope (110 mV and 180 mV/dec at 10 mA/cm2), as well as the RCT value of about 12.26 Ω, determined from Nyquist plot. PANI composite structural characteristics and electrical conductivity have also resulted in a faster rate of electron charge transfer and more accessible surface edge active sites. In addition, the catalyst is stable for 48 h at the specified operating conditions, and no further buffered electrolytes are required. As a result of the enhanced electrochemical performance, a strategic approach for the development of low-priced electrocatalysts for power conversion has been discovered.