Polyaniline Fibers Research Articles

High-performance PANI sensor on silicon nanowire arrays for sub-ppb NH3 detection

For industrial production and disease diagnosis, real-time detection of low concentrations of NH3 is crucial, necessitating a gas-sensitive sensor compatible with integrated processes and exhibiting excellent performance. Herein, we employed wet etching and rapid in-situ polymerization on silicon nanowire substrates to grow polyaniline fibers, thereby fabricating NH3 gas sensors with p-p heterojunction and three-dimensional network structures. Characterization and gas sensing performance testing were conducted. The results demonstrate the outstanding NH3 detection capabilities of the sensor, providing stable responses down to concentrations as low as 1 ppb, which indicates its LOD is one to two orders of magnitude lower than current similar products. It also exhibits verified selectivity and long-term reliability. The excellent sensing performance is attributed to the high surface area from the silicon nanowire structure and efficient synergy of p-p heterojunction. Additionally, the influence of doping types of the substrates and annealing process were explored. This work serves as a reference for the design of silicon-based gas sensors with high sensitivity, low detection limits, and extended operational lifetimes, suitable for deployment in commercial integrated monitoring systems.

Enhanced thermoelectric properties of carbon nanotubes/polyaniline fibers through engineering doping level and orientation

The rapid progress of miniaturized wearable electronics has put forward great requirements for organic fiber-based thermoelectric (TE) generators. Despite polyaniline (PANI) exhibits many outstanding attributes such as facile synthesis and low cost, as well as good environmental and thermal stability, only a few PANI-based fibers were fabricated and their TE efficiency needs to be further improved. In this work, the TE performance of wet-spun carbon nanotubes (CNTs)/PANI fibers was improved by synergistic engineering doping level of PANI and orientation of the fibers. The doping degree was optimized by varying coagulation baths, bath durations, and dopant loadings in the spinning solution, followed by fixing process during air drying to decrease shrinkage and enhance orientation of the fiber. Hexane coagulated CNTs/PANI fibers exhibited a higher doping degree of PANI compared to that of acetone and ethyl acetate, resulting in a maximum TE power factor of 77.4 μW m−1K−2 for 71 wt% CNTs/PANI fibers at PANI/dopant molar ratio of 2:1.25. Further fixing process induced a more oriented structure along the fibers, facilitating carrier transport and contributing to a significantly increased conductivity of 2155 S cm−1. Consequently, the CNTs/PANI fibers reached an optimal power factor of 91.8 μW m−1K−2. With outstanding TE performance and mechanical properties, the resultant fibers were assembled to fabricate a flexible TE generator, which generated a high output power of 2.5 nW with a temperature gradient of 10 K. These results demonstrate the potential of high-performance CNTs/PANI fibers to harvest body heat for the power supply of the wearable electronics.

Facile synthesis of PA photocatalytic membrane based on C-PANI@BiOBr heterostructures with enhanced photocatalytic removal of 17β-estradiol

The prevalence of 17β-estradiol (E2) in wastewater has attracted widespread attention due to the negative impacts on ecological environments and human health. Nowadays, photocatalysis has been emerged as an efficient technology for E2 containing wastewater treatment. However, traditional powder photocatalysts face challenges such as easy agglomeration, secondary pollution and difficult recovery, limiting their large-scale application. In this study, a photocatalytic PA/C-PANI@BiOBr membrane was fabricated by immobilizing polyaniline (PANI) layer and BiOBr nanosheets on polyamide (PA) membrane through in-situ chemical bath deposition. This process leveraged the strong hydrogen bond interaction between PANI and PA, with the fine PANI fibers providing nucleation sites for the in-situ growth of BiOBr nanosheets. By repeating the immersion process, we controlled variations in the coverage density and morphology of BiOBr on the membrane surface. The PA/C-PANI@BiOBr membrane exhibited outstanding light absorption and photocatalytic performance. Notably, the optimal PA/C-PANI@BiOBr-10 membrane achieved 100 % removal efficiency of 3 mg L−1 E2 within 40 min. In dynamic cyclic experiments, PA/C-PANI@BiOBr-10 membrane maintained stable permeability and high removal efficiency of pollutants. The photocatalytic mechanism underlying these results was elucidated through photoelectric testing and further photocatalytic experiments. Furthermore, the PA/C-PANI/BiOBr-10 membrane demonstrated remarkable durability over multiple consecutive cycles, with E2 removal efficiency remaining above 96.5 % after 5 cycles.

Pengaruh Suhu Terhadap Sifat Listrik Polimer Konduktif Polianilin TiO2 Berpenguat Nano Serat Pinang

This research serves to see the effect of temperature on conductive polymers, and the temperature variations used are 27 ℃, 37 ℃, 47 ℃, 55 ℃, 67 ℃, and 77 ℃. The polyaniline used is pure polyaniline and a mixture of polyaniline, TiO2, and nano areca fiber with a mixture percentage of 70%: 27%: 3%. Polyaniline is produced from polymerization of aniline monomer and ammonium peroxydisulfate and nano arecafibers are used from nano arecafibers that have been produced in previous research. Electrical properties testing consisted of electrical conductivity and capacitance tests using an LCR meter. The results showed the lowest conductivity value at 27 ℃ was 0.18 × 10-2 S /cm, and the highest conductivity value at 77 ℃ was 1.22 × 10-2 S/cm for pure polyaniline, while the mixed polyaniline obtained the lowest conductivity value at 27 ℃ was 0,85 × 10-2 S/cm, and the highest value at 77 ℃ was 3.61 × 10-2 S/cm. For the capacitance test, the highest value was obtained at 6.8 μF and 18.9 μF. From the results obtained, the higher the temperature, the higher the conductivity value produced, while the capacitance results show that the higher the temperature used, the lower the capacitance value.

Agile soft template array fabrication of one-dimensional (1D) polyaniline nanocomposite fibers for hydrogen storage.

Polyaniline-Zn/V2O5 nanocomposites were prepared in the presence of toluene-4-sulfonic acid monohydrate as an anionic surfactant via an in situ oxidation polymerization method. The structural study of the nanocomposites was carried out using FTIR and XRD analysis, and their surface morphology was characterized through SEM analysis. The BET surface area of a 3 wt% nanocomposite was 386 m2 g-1, which is higher compared to that of PANI. The Kelvin two probe method was used to study DC conductivity, and it was found that the conductivity increases with increasing temperature. Among all the PANI nanocomposites, 3 wt% PANI-Zn/V2O5 shows a high conductivity of 13.8 S cm-1. Cyclic voltammetry results show the characteristic oxidation-reduction peaks at 0.93 V and 0.24 V for polyaniline and its nanocomposites, respectively. Hydrogen absorption studies were carried out using volumetric sorption measurement technique. At room temperature, it was found that the hydrogen adsorption capacity of polyaniline fibres is about 4.5 wt%, and its absorption capacity increases two-fold upon increasing the temperature up to 60 °C. Conversely, the 3 wt% PANI-Zn/V2O5 nanocomposite showed a high absorption capacity of 6.6 wt% compared with other compositions, which is may be due to the presence of nitrogen (N) molecules in polyaniline and its particular porous fiber architecture.

Development of an all‐electrospun high‐performance textile supercapacitor for wearable device applications

AbstractThis paper reports the synthesis and electrochemical performance of electrospun polyaniline (PANI) nanofiber membranes that work as high‐performance electrodes in an all‐textile supercapacitor (SC). The electrospun separator membrane consists of a mix of polyacrylonitrile (PAN) and poly (ethylene sulfonate) (PES). The all‐textile SC consists of a PES‐PAN membrane, previously soaked in an electrolyte, stacked between two PANI fiber electrodes. Scanning electron microscopy and Fourier‐transform infrared spectroscopy are carried out to characterize the morphology and chemical structure of the PANI and PES‐PAN fiber membranes. Cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy are carried out to characterize the electrochemical properties of the SCs. The all‐textile SC shows very competitive specific capacitances of 275 F/g at 0.25 A/g and a maximum specific power of 1350 Wkg−1. These all‐electrospun SCs show higher performance than the SCs using PANI films and commercial cellulose as separators. Finally, we report a flexible all‐electrospun and all‐solid‐state SC was fabricated using flexible substrates and a gel‐type electrolyte. Flexible SC has a specific capacitance of 270 F/g, confirming that the performance of all‐electrospun SCs is a promising approach for future textile energy storage devices for its potential use in wearable devices.

Eco-Friendly AMPS-Doped Polyaniline/Urethane-Methacrylate Coating as a Corrosion Protection Coating: Electrochemical, Surface, Theoretical, and Thermodynamic Studies

In this study, 2-acrylamido-2-methylpropanesulfonic acid (AMPS)-doped polyaniline (PANI) fibers were used as polymerizable smart anticorrosive agents to prepare eco-friendly UV-curable anticorrosive coatings. For this purpose, AMPS-doped PANI fibers were synthesized through chemical oxidative interfacial polymerization. The size and chemical structure of the prepared conducting fibers were characterized by scanning electron microscopy, 1H NMR, and Fourier transform infrared (FTIR) analyses. As a binder for the prepared conducting fibers, an eco-friendly fluorinated urethane-methacrylate dispersion was synthesized and fully characterized using FTIR analysis. Subsequently, various amounts of the synthesized fibers were mixed with the fluorinated binder to prepare UV-curable anticorrosive coatings. The physicochemical interactions between the PANI fibers and UV-curable binder were studied thoroughly using differential scanning calorimetry and thermogravimetric analyses and measurement of the gel contents and adhesion strength of the prepared composite coatings. The corrosion resistance performance of the prepared coatings was evaluated using electrochemical impedance spectroscopy analysis, and the obtained results revealed that the presence of 2 wt % of the AMPS-doped PANI fibers significantly enhanced the corrosion resistance of the obtained coating. In addition, the corrosion layers of the coatings were analyzed using X-ray photoelectron spectroscopy, which indicated that the AMPS-doped PANI fibers changed the composition of the corrosion product layer. To expand these attempts, this study also explores the interaction of AMPS-doped PANI fibers with the Fe(100) surface using density functional theory as well as atom in molecule calculations. All of the obtained results proved that the outstanding corrosion protection performance of the prepared composite coatings originated from exceptional chemical interactions between the unsaturated doping agents of the prepared PANI fibers and the UV-cured polymer.

Preparation of Anionic Surfactant-Based One-Dimensional Nanostructured Polyaniline Fibers for Hydrogen Storage Applications

Polyaniline fibers were prepared in the presence of anionic surfactant in an ice medium to nucleate in one dimension and were compared to bulk polyaniline prepared at an optimum temperature. Fourier-transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD) were used to investigate the structural analysis of the prepared samples. A conductivity study reveals that polyaniline fibers have high conductivity compared to bulk polyaniline. Hydrogen storage measurements confirm that the polyaniline fibers adsorbed approximately 86% of the total actual capacity of 8-8.5 wt% in less than 9 min, and desorption occurs at a lower temperature, releasing approximately 1.5 wt% of the hydrogen gases when the pressure is reduced further to 1 bar.

Effect of TiO2 on the electrical conductivity of Polyvinyl alcohol- Polyaniline film

Polyvinyl chloride (PVA)-Polyaniline (PANI) nanocomposite films with different weight percentages of TiO2 (1%, 2%, 4%) were prepared. The morphology of the PANI fibers and the prepared films are characterized by field emission scanning electron microscopy, and the absorption spectra of the films are observed by a Hitachi UV spectrophotometer. The variation of electrical conductivity with frequency was measured using a 1 M 3570 impedance analyser showing that the conductivity of the film depends on TiO2 nanoparticles at room temperature studied.

Determination of the angle of rotation of the diffraction grating by the method of conical diffraction

Diffractograms of rotated polyaniline fiber grating were studied experimentally. Based on the obtained results, the diffraction patterns were analyzed and set of experimental data obtained after image digitization was approximated by the least squares method. The angle of rotation of the diffraction grating was calculated using the determined coefficients of the second-order curves.

EM waves absorption properties of nitrogenous porous carbon derived from PANI fiber clusters carbonization

The carbon source, graphitization degree and microstructure of pure carbon materials have strong effects on their electrical conductivity, impedance matching and electromagnetic (EM) waves absorption properties. A novel microstructure nitrogenous porous carbon (NPC) material with excellent EM waves absorption properties was synthesized by carbonizing polyaniline (PANI) fiber clusters. When the filler loading is only 30 wt%, the widest effective absorption bandwidth (EAB) reached 5.5 GHz from 12.41 GHz to 17.91 GHz (almost the entire Ku band) with a thickness of only 1.5 mm and the EAB/thickness was up to 3.67 GHz/mm, which is not inferior or even better than many composites with complex structure. The nitrogen atoms in NPC lattice reduced its graphitization degree. The synergistic effect of optimized impedance matching and enhanced dielectric loss improved EM waves absorption of NPC. The EM waves dissipation mechanisms of NPC material mainly include dipole polarization, interface polarization and conductance loss. The synthesized NPC is a potential EM waves absorption material.

Electrospinning of Polyaniline (PANi) Nanofibers: Effect of Electrospinning Parameters on the Conductivity of Electrospun Nanofibrous Mats

In this work, we have developed a new protocol to prepare conductive polyaniline (PANi) nanofibrous mats via an electrospinning process. The newly developed method started with doping pure polyaniline with concentrated sulphuric acid. The doped PANi is then blended with other spinnable polymers such as Polyacrylonitrile (PAN). The prepared blend is then converted into a solid nanofibrous mat using an electrospinning process. Different parameters, such as solution weight fractions, electrospinning voltage, and feed rate, were optimized and their effect on fibre morphology and conductivity were studied. Several measurement techniques were used to assess the properties of the developed mats. The measurements include Field Emission Scanning Electron Microscopy (FESEM), the intrinsic conductivity of PANi fibres and the conductivity of fibrous mats. Results revealed a direct relationship between the average fibre diameter and the morphology and the conductivities of both the fibres and the mats. Doped polyaniline showed higher conductivity compared with the pure one with an increase in average fibre diameters. Blending polyaniline with PAN improved the mat's morphology and affects their conductivities. In addition, electrospinning process parameters such as feed rate and applied voltage showed a major effect on the fibre’s morphology and conductivity.

High specific surface area triphenylamine-based covalent organic framework/polyaniline nanocomposites for supercapacitor application

Covalent organic frameworks (COFs) possess extraordinary porosity, structural diversity, and good electrochemical performance, and have broad application prospects in the field of energy storage. However, the low conductivity of COFs limits its further development. In this paper, the electrochemical performance of triphenylamine-based COFs (TPA-COFs) was improved by compounding with highly conductive polyaniline (PANI) using solvothermal synthesis process. The highly conductive polyaniline fibers can act as conductive path in the composite to accelerate the charge transfer rate of TPA-COFs. The π-π interaction between TPA-COFs and PANI effectively decreases the agglomeration degree of PANI. The good dispersion of composite results in that the specific surface area of TPA-COFs/PANI-20 is high as 1233.9 m2 g−1, which provides rich diffusion channels for electrolyte ions. Moreover, the strong π-π structure in the composites ensures the stability of the material skeleton. Thus, TPA-COFs/PANI composite exhibits excellent rate characteristics and cycling stability.

Effect of doping ratio and amount of polyaniline, cobalt ferrite, and carbon fiber powder on the electromagnetic properties of coated polyester-cotton fabrics

In this project, polyaniline powder was firstly prepared by in situ polymerization using aniline as the monomer, ammonium persulfate as the oxidant, and camphor sulfonic acid as the dopant. Next, polyester-cotton fabrics were used as the base fabrics, polyaniline, cobalt ferrite, and carbon fiber powder as the functional particles, and PU-2540 type polyurethane as the base, and single-layer coated polyester-cotton fabrics were prepared by the textile coating process. Finally, the effects of the polyaniline, cobalt ferrite, and carbon fiber powder doping ratio and functional particle content on the shielding effectiveness, reflection loss, real and imaginary parts of the dielectric constant, and loss angle tangent of single-layer coated polyester-cotton fabrics were focused on using the controlled variable method. The results show that in the frequency range of 0.01–3 GHz, when the doping ratio of polyaniline, cobalt ferrite, and carbon fiber powder is 1:0:3, and when the content of functional particles is 40%, the minimum reflection loss of single-layer coated polyester-cotton fabrics is –22.1 dB at 1.6 GHz, and the effective absorption bandwidth is 1.14 GHz.

Fabrication of Polyaniline Structures for Enhanced Supercapacitance: Effect of PANI Morphologies

This work is conducted with the aim to see the effect of Polyaniline (PANI) morphologies on the specific capacitance of the electrode material. The paper presents a low-temperature synthesis and electrochemical analysis of PANI morphologies (granular, pebbles, spheres, tubes, flakes, and fibers). The supercapacitive behavior of all fabricated electrodes was tested via a two-electrode setup in 0.1 M H2SO4 electrolyte. The electrochemical analysis showed that amongst all the PANI morphologies, nanofibers had the highest specific capacitance (752.27 Fg-1), a good energy density (66.86 Whkg-1), and a good retention rate (40%). The reason may be attributed to a larger π-π stacking interaction with maximum d-spacing (3.52 Aº) that gives a desirable contact surface area for the electrolyte ions to transport efficiently across the electrolyte. Also, it has a low value of Rb (4.67 W), Rct (0.56 W), a good (251 Hz), a very less relaxation time (0.0039s), and a high knee frequency value (825.2 Hz). PANI fibers can prove to be an effective electrode material that could enhance the specific capacity of the electrode at the same time is economical and environmentally friendly.

Scalable production of ultrafine polyaniline fibres for tactile organic electrochemical transistors

The development of continuous conducting polymer fibres is essential for applications ranging from advanced fibrous devices to frontier fabric electronics. The use of continuous conducting polymer fibres requires a small diameter to maximize their electroactive surface, microstructural orientation, and mechanical strength. However, regularly used wet spinning techniques have rarely achieved this goal due primarily to the insufficient slenderization of rapidly solidified conducting polymer molecules in poor solvents. Here we report a good solvent exchange strategy to wet spin the ultrafine polyaniline fibres. The slow diffusion between good solvents distinctly decreases the viscosity of protofibers, which undergo an impressive drawing ratio. The continuously collected polyaniline fibres have a previously unattained diameter below 5 µm, high energy and charge storage capacities, and favorable mechanical performance. We demonstrated an ultrathin all-solid organic electrochemical transistor based on ultrafine polyaniline fibres, which operated as a tactile sensor detecting pressure and friction forces at different levels.

Nanostructured polyaniline SPME fiber coating for chemical warfare agents analysis

Nanostructured polyaniline (PANI) was electrochemically obtained as a fiber coating of solid-phase microextraction (SPME) and then used in the analysis of selected organoarsenic and organophosphorus compounds in soil samples. Also, comparative studies of the obtained PANI fibers with seven commercially available fibers for varying miscellaneous polarity, and various absorption and/or adsorption natures, were carried out. Quantitative analysis of environmental samples was performed using a gas chromatograph coupled with a tandem mass spectrometer. During the analysis of organophosphorus compounds, the PANI fiber showed at least 20% greater sorption efficiency than any commercially available fiber, whereas, in the case of organoarsenic compounds, the sorption efficiency of the PANI fiber increased with the expansion in the number of phenyl rings in the molecule. The PANI coating material was characterised by N2 adsorption–desorption, scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis. SEM imaging confirmed a nanostructured form of PANI. The repeatability for one fiber (n = 7), expressed as the relative standard deviation ranges from 3.2% to 4.4% depending on the kind of tested chemical compound. The reproducibility (calculated as relative standard deviation of the 9 prepared fibers) was not greater than 7.2% Under the optimized conditions, the proposed method was linear over approximately 4 orders for organophosphorus compounds (0.02–100 ng g−1) and 5 orders for organoarsenic compounds (0.12–5000 ng g−1) of magnitude for the tested compounds, with linear determination coefficients (R2) greater than 0.972, and the limit of detection for the home-made PANI fiber was relatively low (0.006–0.45 ng g−1). In comparison with all commercially available SPME fibers, the new PANI fiber was more selective for the tested aromatic and organophosphorus compounds and easily as well as inexpensively prepared. The resulting stationary phase allowed for quantitative analysis of selected organophosphorus and organoarsenic compounds from the group of warfare agents.

Enhanced electromagnetic wave absorption of engineered epoxy nanocomposites with the assistance of polyaniline fillers

In this work, the engineered polyaniline (PANI)/epoxy composites reinforced with PANI-M (physical mixture of PANI spheres and fibers) exhibit significantly enhanced electromagnetic wave absorption performance and mechanical property. Due to the synergistic effect of PANI fillers with different geometries, the reflection loss of 10.0 wt% PANI-M/epoxy could reach − 36.8 dB at 17.7 GHz. Meanwhile, the mechanical properties (including tensile strength, toughness, and flexural strength) of PANI/epoxy were systematically studied. Compared with pure epoxy, the tensile strength of epoxy with 2.0 wt% PANI-M was improved to 86.2 MPa. Moreover, the PANI spheres (PANI-S) and PANI fibers (PANI-F) were prepared by the chemical oxidation polymerization method and interface polymerization method, respectively. The characterizations including scanning electron microscope, Fourier transform infrared spectra, and X-ray diffraction were applied to analyze the morphology and chemical and crystal structures of PANI filler. This work could provide the guideline for the preparation of advanced engineered epoxy nanocomposites for electromagnetic wave pollution treatment.Graphical abstract

A conductive bio-hydrogel with high conductivity and mechanical strength via physical filling of electrospinning polyaniline fibers

The development of bio-based conductive hydrogel has become the research frontier of flexible sensors. However, it is a challenge to prepare a simple method to prepare bio-based conductive hydrogel with excellent stability, tensile strength, and conductivity. Here, we show a simple strategy to prepare conductive, stretchable, and stable hydrogel (KKLN). The KKLN consists of the conductive polyaniline (PANI) fiber prepared by electrospinning and lithium ions (Li+) in physical form, which has the all-biological matrix with Konjac glucomannan / K-Carrageen (KGM-KC) interpenetrating network structure. In this system, the hydrogel shows remarkable mechanical property (strength: 239.26 kPa, strain: 340.69%) and high conductivity (7261 μs/cm) because contribution of PANI fiber and Li+. And the KKLN exhibits outstanding characteristic on the swelling and heat stability performance. Furthermore, it was confirmed that the prepared hydrogel can accurately monitor the movement of the body parts, including the index finger, elbow, wrist, and knee. Therefore, this prepared method and introduction of the fiber prepared by electrospinning provide a new strategy to promote the further development of flexible sensors based on the biological matrix.

Alternating current based electrochemically polymerized polyaniline modified flexible conducting paper as an exoelectrogenic biofilm platform for a microbial fuel cell

Biofilms of exoelectrogens are known to oxidize organic matter in wastewater. The present study highlights the electrochemical polymerization of polyaniline (PANI) on gold (Au) sputtered cellulosic and nylon papers to develop exoelectrogenic biofilm to be used in a microbial fuel cell (MFC). Polymerization of PANI on Au sputtered papers was performed using direct current (DC) and alternating current (AC) based electrochemical polymerization techniques (viz. cyclic voltammetry (CV), chrono-amperometry (CA), chrono-potentiometry (CP) and electrochemical impedance spectroscopy (EIS)). Among various DC and AC electrochemical routes, the AC route was found to be a better alternative for the electrochemical polymerization of PANI fibres. The outcomes of analytical techniques established the uniform deposition of PANI fibres of 1.12 μm diameter on the Au-supported conducting paper by utilizing the AC electrochemical route. In comparison to PANIEIS/Au/Nylon paper and PANIEIS/Au/Cellulosic paper-based flexible electrodes, the least charge transfer resistance (6.96 Ω) was achieved by conducting paper. The developed conducting paper was incorporated in an MFC to develop exoelectrogenic biofilm. Interactions between the exoelectrogenic biofilm and the conducting paper were confirmed by using Raman spectroscopy. Biofilm grown on PANIEIS/Au/Nylon paper showed better performance than the previously developed PANIEIS/Au/Cellulosic paper. Based on maximum current output the fabricated conducting paper have the potential to be employed in an MFC for the measurement of water quality/toxicity/BOD over a prolonged time without any leaching and fouling.