Conductive Polyaniline Research Articles

In-situ polymerization of dendritic polyaniline nanofibers network embedded with Ag@SiO2 core-shell nanoparticles for electrochemical determination of trace arsenic(III)

Arsenic(III) is a highly toxic pollutant in the environment, and the development of nanomaterials with high electrochemical activity for As(III) detection is a research focus at present. Herein, an electrochemical sensing platform based on polyaniline nanofibers embedded with Ag@SiO2 nanoparticles (Ag@SiO2/PANI NFs) was successfully constructed for trace As(III) determination. Owing to an in-situ chemical oxidation polymerization strategy, the polyaniline nanofibers loaded with Ag@SiO2 core-shell nanoparticles blossomed into the dendritic three-dimensional network. The unique structure with a huge specific surface area greatly enhanced the adsorption efficiency of As(III). Combined with the outstanding conductivity of polyaniline and the electrocatalytic ability of uniformly dispersed AgNPs, the stripping current signal of As(III) was further amplified. Based on the optimized conditions, the sensitivity of 0.83 μA μg−1 L was obtained in the linear range of 0.1 ~ 100 μg L−1 with a low detection limit of 0.013 μg L−1. And the selectivity, reproducibility, and long-term stability of this sensor were excellent. Additionally, satisfactory results were achieved by the recovery experiment of real samples, and the accuracy of this method was verified by comparison with ICP-MS. The above results demonstrated the promising application of the as-fabricated sensor in As(III) detection.

Polyaniline Functionalized Peptide Self-Assembled Conductive Hydrogel for 3D Cell Culture.

The functionalization of self-assembled peptide hydrogel is of great importance to broaden its applications in the field of biomedicine. In this work, conductive hydrogel is fabricated by introducing conductive polymer polyaniline into peptide self-assembled hydrogel. Compared with pure peptide formed hydrogel, the conductive hydrogel exhibits enhanced conductivity, mechanical property and stability. In addition, the hydrogel is tested to be of great injectability and 3D bio-printability and could support the viability of encapsulated cells that are sensitive to electrical signals. It should have great application prospects in the preparation of tissue engineering scaffolds.

Preparation and Performance Study of Carboxy-Functionalized Graphene Oxide Composite Polyaniline Modified Water-Based Epoxy Zinc-Rich Coatings

Graphene oxide is obtained by oxidation of graphite followed by ultrasonic exfoliation. It is a two-dimensional layered material with a large number of oxygen-containing functional groups on its surface. Polyaniline is a conductive polymer and has a unique corrosion protection mechanism. In this study, carboxy-functionalized graphene oxide/polyaniline (CGO/PANI) composites with a lamellar structure were prepared by in situ polymerization. The lamellar layer was used to form a labyrinthine structure in the coating to effectively retard the penetration of corrosive media. The electrical conductivity of polyaniline can promote the formation of conductive pathways between zinc particles and improve the utilization of zinc powder. Polyaniline is also able to passivate the substrate, further improving the coating’s ability to protect steel substrates against corrosion. In this paper, the in situ polymerization of aniline on carboxy-functionalized graphene oxide flakes was confirmed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), and the improvement of the corrosion resistance of the prepared composites on the epoxy zinc-rich coatings was evaluated by SEM, electrochemical impedance spectroscopy (EIS), and salt spray resistance tests. The results showed that aniline was successfully polymerized in situ on carboxy-functionalized graphene oxide, and the modified coating had significantly improved anticorrosive properties, where the best anticorrosive improvement was achieved when CGO: PANI = 0.03.

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.

Surface Modification of γ-Al2O3 Nanoparticles Using Conductive Polyaniline Doped by Dodecylbenzene Sulfonic Acid.

In this study, electrically conductive PANDB/γ-Al2O3 core–shell nanocomposites were synthesized by surface modification of γ-Al2O3 nanoparticles using polyaniline doped with dodecylbenzene sulfonic acid. The PANDB/γ-Al2O3 core–shell nanocomposites were synthesized by in situ polymerization. Pure PANDB and the PANDB/γ-Al2O3 core–shell nanocomposites were characterized using Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, and measurement of a four-point probe. The conductivity of the PANDB/γ-Al2O3 core–shell nanocomposite was about 0.72 S/cm when the weight ratio of aniline/γ-Al2O3 was 3/1. The results showed that the conductivity of the PANDB/γ-Al2O3 core–shell nanocomposite decreased with increasing amounts of γ-Al2O3 nanoparticles. The transmission electron microscopy results indicated that the γ-Al2O3 nanoparticles were thoroughly coated with PANDB to form a core–shell structure. Transmission electron microscopy and field emission scanning electron microscopy images of the conductive PANDB/γ-Al2O3 core–shell nanocomposites also showed that the thickness of the PANDB layer decreased as the amount of γ-Al2O3 was increased.

Fermentation-Inspired Gelatin Hydrogels with a Controllable Supermacroporous Structure and High Ductility for Wearable Flexible Sensors.

Supermacroporous hydrogels have attracted wide concern due to their comfort and breathability in wearable health-monitoring applications. Size controllable supermacroporous structure and excellent mechanical properties are the most important for its application. However, they are normally fabricated by the cryogelation method, which is difficult to control pore size and maintain flexibility. Here, yeast fermentation-inspired gelatin hydrogels with a controllable supermacroporous structure and excellent mechanical properties were fabricated for the first time. The pore size can be controlled by adjusting the content of glucose and yeast, the ratio of glucose to yeast, fermentation time, and gelatin content during fermentation. The hydrogels demonstrated a controllable pore size range from 100 to 400 μm and rapid swelling characteristics. The mechanical properties were maintained by soaking ammonium sulfate solution for 12 h, showing maximum tensile and compressive strains over 300 and 99%, respectively. This novel approach can be easily applied to the preparation of supermacroporous and high ductility hydrogels under mild conditions. Furthermore, conductive hydrogels combined supermacroporous structures with conductive polyaniline and reduced oxidized graphene, and silver nanowires were prepared as wearable flexible sensors. The obtained sensors maintain well-distributed porosity, breathability, and mechanical flexibility, also showing excellent conductivity of 2.4 S m-1. Finally, the sensors were successfully applied to detect physiological signals and human-computer interaction.

Nanoparticles improving polyaniline electrical conductivity: A meta-analysis study

Polyaniline is a conductive polymer that attracts the attention of many researchers around the world. The history of this polymer begins in 1862 when Letheby first reported this material. Since then, a myriad of studies has been conducted onthis material, and new works continue to investigate the potential of this material. Polyaniline has been improved with the help of Nanotechnology. The use of nanofillers has been seen as a quick and economical way to modify materials, drivinginnovations based on new physical and chemical properties from the conductive polymer materials and nanoparticles joining. Several works address the use of different nanoparticles, which leads to the practical impossibility of sifting through all this information. Thus, this work proposes to systematically collect data in the literature and investigate which nanoparticles can increase the electrical conductivity of Polyaniline (PAni). The results obtained demonstrate that among the possiblenanofillers, graphene and carbon nanotubes have great prominence. Furthermore, the results of the meta-analysis prove that PAni's conductivity increases when this polymer is modified with the aforementioned nanofillers.

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.

Waterborne polyurethane‐acrylate‐polyaniline: Interfacial hydrogen bonding for enhancing the antistatic, damping, and mechanical properties

AbstractDamping coatings can convert kinetic energy into other forms of energy for consumption and have been widely used for vibration and noise reduction in rail trains, aerospace, automobile industry, and other fields. However, many aspects of damping coating such as, damping, water resistance, heat resistance, mechanical properties and antistatic properties require further improvement. In this study, a low‐cost conductive polyaniline (PANI) with a simple preparation method was dispersed in N‐methyl pyrrolidone and added to waterborne polyurethane‐acrylate (WPUA) hybrid latexes. The interfacial hydrogen bonding increases the interaction force between molecular chains, effectively improve the water resistance, heat resistance, damping, and mechanical properties of WPUA, and endowed WPUA with antistatic properties. Among them, PANI was used as an antistatic medium to be synthesized by chemical oxidation and doped with dodecylbenzene sulfonic acid, and the matrix polymer WPUA was the used of hydroxyethyl methacrylate (HEMA) to combine polyacrylate with waterborne polyurethane (WPU) by chemical bonds. The waterborne polyurethane‐acrylate‐polyaniline (WPUA‐PANI) films were investigated using dynamic light scattering , contact angle measurements , dynamic mechanical analysis, Fourier‐transform infrared spectroscopy (FTIR), digital highresistance meter and other characterization methods. It was concluded that the base latex has good stability, and when the PANI dispersion content was 35%, the comprehensive performance of the WPUA‐PANI films were the best, in which the maximum water contact angle was 106.8°, the tensile strength was increased from 0.7 MPa to 2.3 MPa, the effective damping temperature range (Tanδ ≥ 0.3) was increased from 50 °C to 87 °C, and the resistivity was reduced from 6.41E + 7 Ω·cm to 1.38E + 4 Ω·cm, which had better antistatic properties. This study will promote the development and application of damping coatings.

Breathable Nanomesh pressure sensor with layered polyaniline grown at Gas-liquid interface

High performance pressure sensing device fabricated by coating conductive polymers on flexible substrates attracts research focuses in the field of wearable devices currently. The most common method for polymerization of conductive polyaniline (PANI) in aqueous solution, generally causing problems of damage to flexible substrate, poor effect of polymerization and environmental pollution. In this study, a novel low-temperature gas–liquid interface polymerization method for PANI polymerization is developed to fabricate core–shell conductive fibrous membrane. By skillfully taking advantage of volatility of aniline monomer, layered conductive PANI grows vertically on the surface of electrospun fibers at gas–liquid interface instead of in traditional aqueous solution. The degree of PANI polymerization based on this method is controllable by glycerin, which can be analyzed by an established model. The sensor fabricated by this method demonstrates superior performance with a high sensitivity of 10.62 kPa−1, fast response time (60 ms) and subtle detection limit (5.1 Pa) compared with that prepared by traditional liquid polymerization. This breathable sensor can detect human signal detection effectively, and develop a variety of intelligent applications. In brief, this work provides a novel strategy and facile technology for developing flexible intelligent devices with conductive polymers.

P-doped PANI/AgMWs nano/micro coating towards high-efficiency flame retardancy and electromagnetic interference shielding

With the rapid development of 5G technology, functional coatings with both high-efficiency flame retardancy and electromagnetic interference shielding (EMI) are urgently needed, while traditional inefficient methods have encountered bottlenecks. Herein, we demonstrate an eco-friendly and multifunctional nano/micro coating constructed by biomass phytic acid (PA) induced polymerization and self-assembly of polyaniline (PANI) nanoparticles and dip-coating of silver microwires (AgMWs). In this design, PA with high flame-retardant efficiency is smartly doped into PANI to achieve P-N synergistic flame retardancy and improve electrical conductivity of PANI simultaneously. Consequently, under the coaction of AgMWs, P-doped PANI nanoparticles, as well as unique continuous micro-nano structures, the nano/micro coating can endow commercial polyurethane (PU) foams with outstanding EMI shielding performance (∼51 dB in X-band). Meanwhile, the coated PU foam exhibits high flame retardancy due to the P-N synergistic effect of PA/PANI, which self-extinguishes immediately after ignition during the UL-94 vertical burning test, shows a high limiting oxygen index (LOI) value of 34.8%, and exhibits a 50.7% lower peak heat release rate compared with pure PU foam. Further, the functional nano/micro coating with three-dimensional and highly porous structure makes the foam thermally insulating and infrared stealthing. The eco-friendliness and simplicity of this method and its successful application in commercial PU foam make it potentially applicable for the preparation of various kinds of multifunctional EMI shielding materials.

Electrical Conductivity of SDBS-Assisted Polyaniline Doped with HCl

In this study, polyaniline (PANI) was synthesized through oxidative polymerization assisted by sodium dodecylbenzene sulfonate (SDBS) in hydrochloric acid (HCl) concentration solution to investigate the effect of dopants in the electrical conductivity of polyaniline. The polyaniline obtained from the oxidative polymerization was confirmed with FTIR. The x-ray diffraction pattern showed that polyaniline is semi-crystalline. SDBS does not only act as a template for oxidative polymerization but also acts as a dopant. The dielectric constant, the dielectric loss, and the ac conductivity increase as polyaniline is doped with SDBS, HCl, or with both SDBS and HCl.

Bioinspired hierarchical polydimethylsiloxane/polyaniline array for ultrasensitive pressure monitoring

Flexible pressure sensors based on contact resistance change have the advantages of low temperature dependence and fast response, but their sensitivity and pressure sensing range are limited by the deformation level of the surface structures. Inspired by the hierarchical structure of insect touch receptors, where the primary mechanoreceptor organs have the basic tactile sensing elements and the secondary bristles or tactile hairs maximize signal transduction, we design a hierarchical structure-based pressure sensor consisting of polydimethylsiloxane (PDMS) micropillars and conductive polyaniline (PANI) nanoneedles. Owing to this unique structure, this sensor exhibits ultrahigh sensitivity of 258.7 kPa−1, ultralow detection limit of 0.68 Pa, fast response time of 30 ms and excellent cycle stability over 10,000 cycles. In addition, the pressure sensor shows promising potential in human physiological signal monitoring, such as wrist pulse, throat behavior, finger bending and biceps movements. Evidently, this hierarchical PDMS/PANI structure-based piezoresistive sensor provides an alternative design path for high-performance pressure sensors.

Decavanadate Doped Polyaniline for Aqueous Zinc Batteries.

Polyaniline (PANI) is a promising cathode material for aqueous rechargeable zinc batteries (ARZBs), mainly benefitting from its good electrical conductivity. The high conductivity of PANI requires high doping level, yet the introduced nonactive dopants (e.g., SO4 2- ) limit the gravimetric capacity of PANI (usually <180 mAh g-1 ). Herein, an electro-active dopant (decavanadate anion, V10 O28 6- ) is employed to fabricate the PANI cathode (PANI-V10 O28 ) for ARZBs. The doped decavanadate anion with the sub-nanometer structure can fully expose the V-based active sites, exhibiting good electrochemical activity. Due to the steric hindrance effect as well as the strong interaction between decavanadate anions and PANI chains, the active dopants are trapped in the polymer chains, demonstrating good structural and electrochemical stability. PANI-V10 O28 achieves a record-high gravimetric capacity of 355 mAh g-1 at 0.1 A g-1 , which is significantly higher than other reported PANI cathodes. Experimental results suggest that the charge storage mechanism of PANI-V10 O28 includes reversible injection/extraction of Zn(H2 O)2 Cl4 2- ions in PANI, as well as the protonation/deprotonation of V10 O28 6- . This work enriches the doping chemistry of conducting polymer and pushes the development of organic cathodes for ARZBs to a new stage.

A novel molecularly imprinted polymer composite based on polyaniline nanoparticles as sensitive sensors for parathion detection in the field

This paper presents a novel strategy for the real-time detection of organophosphate pesticides by imprinting parathion molecules at the surface of conductive functional polyaniline nanoparticles (PANIs). It has been demonstrated that the introduction of vinyl group on the surface of PANIs is not only beneficial to the selectivity of imprinting polymerization, but also to the preconcentration of parathion template into the polymer by charge attraction between the template and the functionalized PANIs. Through the above two effects, parathion imprinted polymer was successfully prepared on the surface of PANIs. When the novel material was used to detect parathion in vegetable samples, its selectivity coefficient was observed to be nearly ten times than that of its non-imprinted counterpart. It also possessed high selectivity toward parathion in comparison to structurally similar pesticide compounds. There was a linear relationship between the reductive peak current and parathion concentrations from testing concentrations ranging from between 3.40 × 10 −8 M to 1.87 × 10 −5 M with a detection limit of 1.13 × 10 −8 M (S/N = 3). These results indicate that the newly developed sensor is highly effective for the detection of parathion, and establish the potential of the molecular imprinting approach for future analysis of other organophosphate pesticides. • A novel MIP electrochemical sensor was constructed to determinate trace parathion. • PANIs were functionalized by vinyl group to benefit the imprinting polymerization. • Parathion template could be pre-concentrated at FUN-PANIs by charge attraction. • FUN-PANI-MIPs displayed excellent selectivity and high sensitivity to parathion. • The study was applied for real-time detection of parathion in vegetable samples.

Functional Polyaniline/MXene/Cotton Fabrics with Acid/Alkali-Responsive and Tunable Electromagnetic Interference Shielding Performances.

Although two-dimensional transition-metal carbides (MXenes) and intrinsic conductive polymers have been combined to produce functional electromagnetic interference (EMI) shielding composites, acid/alkali-responsive EMI shielding textiles have not been reported. Herein, electrically conductive polyaniline (PANI)/MXene/cotton fabrics (PMCFs) are fabricated by an efficient vacuum filtration-assisted spray-coating method for acid/alkali-responsive and tunable EMI shielding applications on the basis of the high electrical conductivity of MXene sheets and the acid/alkali doping/de-doping feature of PANI nanowires. The as-prepared PMCF exhibits a sensitive ammonia response of 19.6% at an ammonia concentration of 200 ppm. The high EMI shielding efficiency of ∼54 dB is achieved by optimizing the decorated structure of the PANI/MXene coating on the cotton fabrics. More importantly, the PMCF can act adaptively as a "switch" for EMI shielding between the efficient strong shielding of 24 dB and the inefficient weak shielding of 15 dB driven by the stimulation of hydrogen chloride and ammonia vapors. This multifunctional fabric would possess promising applications for intelligent garments, flexible electronic sensors, and smart electromagnetic wave response in special environments.

Bioinspired facilitation of intrinsically conductive polymers: Mediating intra/extracellular electron transfer and microbial metabolism in denitrification

Intrinsically conductive polymers, polyaniline and polyaniline sulfonate (PASAni) were used to explore their effect on denitrification. Denitrification was accelerated 1.90 times by 2 mM PASAni and the possible mechanisms were mainly attributed to the accelerated electron transfer and the enhanced microbial metabolism activity. Intracellular electron transfer was accelerated by PASAni and the acceleration sites were from NADH to coenzyme Q (CoQ), quinone loop, from Complex II to CoQ and from QH2 to Cyt. c1. Extracellular electron transfer was accelerated because PASAni promoted more secretion of redox species and PASAni embedded in extracellular polymeric substance (EPS). Moreover, PASAni itselfprovided more electron transfer pathways as redox species. Microbial metabolism activity was also enhanced by PASAni, which was reflected in the increased nitrate/nitrite reductase activity (236.13/155.43%), electron transfer system activity (112.49%), adenosine triphosphate level (133.41%) and EPS content (189.06%). Besides, the enriched Proteobacteria in PASAni supplement system was also conducive to denitrification. This work provided fundamental information for conductive polymers mediating microbial electron transfer and enhancing contaminants biotransformation.

All-State Switching of the Mie Resonance of Conductive Polyaniline Nanospheres.

Polyaniline (PANI), a conductive polymer, is a promising active material for optical switching. In most studies, active switching has so far been realized only between two states, whereas PANI has a total of six states. The optical properties of nanoscale PANI in all six states have remained unclear. Herein we report on all-state switching of the Mie resonance on PANI nanospheres (NSs) and active plasmon switching on PANI-coated Au nanodisks (NDs). All-state switching of differently sized PANI NSs is achieved by proton doping/dedoping and electrochemical methods. Theoretical studies show that the scattering peaks of the individual PANI NSs originate from Mie resonances. All-state switching is further demonstrated on PANI-coated circular Au NDs, where an unprecedentedly large plasmon peak shift of ∼200 nm is realized. Our study not only provides a fundamental understanding of the optical properties of PANI but also opens the probability for developing high-performance dynamic media for active plasmonics.

Fabrication and characterization of heterojunction made of porous silicon and polyaniline synthesized by chemical and electrochemical routes

Polyaniline (PANI) samples were deposited through chemical and electrochemical routes onto macroporous silicon (MPS). Their chemical and electrical features were investigated. For this, Fourier transforms infrared, Raman, and energy dispersive spectroscopies were used to show the successful incorporation of PANI into the pores and the formation of silicon oxide as a consequence of the silicon instability in the aqueous solution. The electrical parameters extracted by fitting the current-potential curves using the thermionic emission model of two opposite diodes being one at the PANI/MPS interface and the other at the silicon/back contact, indicate a Schottky barrier of about 0.730 V at the first interface and between 0.795–0.840 V at the second one and becomes more significant in the measurements between two contacts at the PANI surface. The chemical analysis reveals the presence of silicon oxide in both structures. This compound was found to be the determining factor for changing the electrical behavior. A larger flat band was measured in the device made by the chemical synthesis of PANI. The impedance analysis has shown that charge transfer is determined not only by the PANI and silicon oxide conductivity but also by the depletion layer's electrical features. However, the differential activation energy analysis indicates that PANI is chemically deposited, and the charge transport occurs hopping conduction. In contrast, in the electrochemically one, the charge is through impurity band conduction.

Fabrication of Ti3C2Tx MXene/polyaniline composite films with adjustable thickness for high-performance flexible all-solid-state symmetric supercapacitors

In here, we successfully fabricated flexible Ti3C2Tx (MXene)/polyaniline (PANI) films with adjustable thickness by changing the amount of PANI nanofibers utilized as high-performance supercapacitor electrode materials. Firstly, MXene nanosheets and PANI nanofibers were prepared by the minimum strength stratification method and the redox method, respectively. And then the MXene/PANI films were synthesized by simple physical mixing and suction filtration of these two components. The electrochemical performances of the composite films show that the introduction of PANI nanofibers increases the specific capacitance of the MXene film. The reason is that conductive PANI nanofibers can not only provide a path for charge carriers, but also increases MXene layer spacing beneficial to electrolyte ion infiltration. However, with increasing amount of PANI nanofibers, the specific capacitance of the composite film shows a trend of first increase and then decrease. This fact is a result of that excess PANI nanofibers lead to an increase in the thickness of the composite film, which increases the ion and electron transport paths. The assembled device based on the optimal composite film exhibits a high specific capacitance of 272.5 F g−1 at 1 A g−1 and a capacitance retention rate of about 71.4% after 4000 cycles at 2 A g−1. The devices exhibited a high energy density of 31.18 Wh kg−1 at a power density of 1079.3 W kg−1, indicating that it has excellent energy storage performance.