Electropolymerization Of Polyaniline Research Articles

Development of an osmosis-assisted hollow microneedle array integrated with dual-functional electrochemical sensor for urea and pH monitoring in interstitial fluid

In healthcare, accurate detection of biomarkers is paramount for disease diagnosis, prevention, and personal health surveillance. This study focused on developing and validating a MgCl2 deposited hollow microneedle array integrated with a dual-functional sensor system, which was used for osmosis-assisted boosted interstitial fluid extraction, the simultaneous and continuous monitoring of urea and pH in interstitial fluid. The urea sensor component was fabricated by electro-depositing prussian blue onto a carbon electrode, followed by applying a molecularly imprinted polymer layer, ensuring high specificity and sensitivity. The pH sensor was constructed through electropolymerization of polyaniline, exhibiting a linear response across a wide pH range. When tested in artificial skin matrix, the system demonstrated excellent in vitro electrochemical sensing performance with high linearity and repeatability. At the same time, the practical in vivo sensing performance of the system was verified in Sprague-Dawley (SD) rats. The development of the system underscores its potential as a valuable tool for continuous health monitoring.

Exfoliated 2D Nanosheet-Based Conjugated Polymer Composites with P-N Heterojunction Interfaces for Highly Efficient Electrocatalytic Hydrogen Evolution.

They have achieved a significant breakthrough in the preparation and development of two-dimensional nanocomposites with P-N heterojunction interfaces as efficient cathode catalysts for electrochemical hydrogen evolution reaction (HER) and iodide oxidation reaction (IOR). P-type acid-doped polyaniline (PANI) and N-type exfoliated molybdenum disulfide (MoS2) nanosheets can form structurally stable composites due to formation of P-N heterojunction structures at their interfaces. These P-N heterojunctions facilitate charge transfer from PANI to MoS2 structures and thus significantly enhance the catalytic efficiency of MoS2 in the HER and IOR. Herein, by combining efficient sodium-functionalized chitosan-assisted MoS2 exfoliation, electropolymerization of PANI on nickel foam (NF) substrate, and electrochemical activation, controllable and scalable Na-Chitosan/MoS2/PANI/NF electrodes are successfully constructed as non-noble metal-based electrochemical catalysts. Compared to a commercial platinum/carbon (Pt/C) catalyst, the Na-Chitosan/MoS2/PANI/NF electrode exhibits significantly lower resistance and overpotential, a similar Tafel slope, and excellent catalytic stability at high current densities, demonstrating excellent catalytic performance in the HER under acidic conditions. More importantly, results obtained from proton exchange membrane fuel cell devices confirm the Na-Chitosan/MoS2/PANI/NF electrode exhibits a low turn-on voltage, high current density, and stable operation at 2 V. Thus, this system holds potential as a replacement for Pt/C with feasibility for applications in energy-related fields.

In situ growth of CaMoO4 on electropolymerized PANI as a hybrid electrocatalyst for enhanced oxygen evolution.

Electrochemical water splitting stands as a promising avenue for sustainable hydrogen production, with the oxygen evolution reaction (OER) playing a pivotal role. Efficient and durable electrocatalysts are crucial for expediting the sluggish kinetics of OER. In this work, we investigate the synthesis and performance of a novel CaMoO4/polyaniline (CaMoO4/PANI) composite catalyst for OER. In situ growth of CaMoO4 has been done after the electropolymerization of polyaniline on nickel foam (NF), offering advantages such as improved structural integrity, increased surface area, and enhanced electroconductivity. Electrochemical characterization reveals that CaMoO4/PANI exhibits superior catalytic activity, with an overpotential of 233 mV at 10 mA cm-2, outperforming pristine CaMoO4, PANI, and certain current similar non-noble-metal electrocatalysts. Electrochemical studies reveal that the exceptional activity can be attributed to reduced charge transfer resistance, underscoring the catalyst's enhanced efficiency. Furthermore, multistep chronopotentiometry confirms excellent robustness of the catalyst electrode as well as its excellent mass transportation. This work highlights the potential of inorganic oxide/conductive polymer composites as efficient catalysts for OER, offering insights for future developments in sustainable energy technologies.

Evaluation of Supercapacitive Properties of a PPY/PANI Bilayer Electrodeposited onto Carbon-Graphite Electrodes Obtained from Spent Batteries

Recently, many efforts have been made to reuse spent batteries in response to the growing demand for sustainable materials production. In parallel, supercapacitors have attracted significant attention for their use in addressing some of the limitations of conventional capacitors and batteries. In this context, this paper describes the preparation, characterization, and supercapacitive performance evaluation of carbon-graphite (CG) electrodes obtained from spent zinc–carbon batteries and modified with polypyrrole (PPY) and polyaniline (PANI). The parameters of PPY and PANI electropolymerization were optimized. CG/PPY, CG/PANI, and CG/PPY/PANI electrodes were obtained to compare their electrochemical responses. Cyclic voltammetry (CV), galvanostatic charge–discharge curves (GCDC), and electrochemical impedance spectroscopy (EIS) were used to evaluate the pseudocapacitive properties of the CG/PPY/PANI-modified electrode. The CG/PPY/PANI electrode showed a specific capacitance of 3416 mF cm−2 in a current density of 2 mA cm−2 and a retention capacity of 76% after 850 GCDC cycles. Thus, CG/PPY/PANI electrodes are shown to be good candidates for use in the development of energy storage devices. In addition, reused CG electrodes from spent batteries have other advantages like low cost, facile construction, and environmental friendliness.

Peptide-antifouling interface for monitoring β-amyloid based on electrochemiluminescence resonance energy transfer

In this study, a novel antifouling electrochemiluminescence (ECL) analytical platform has been developed for the highly sensitive quantification of β-amyloid (Aβ) peptides based on the ECL resonance energy transfer (ECL-RET) mechanism. Specifically, glassy carbon electrodes (GCE) were initially coated with graphite-phase carbon nitride (g-C3N4) nanosheets, followed by the electropolymerization of polyaniline (PANI) onto the electrode surface. Subsequently, a promising peptide motif candidate (COOH-CPPPPDKDKDKDKKLVFF) was immobilized onto the PANI-modified electrode, functioning as a critical component for both antifouling and specific recognition of full-length Aβ peptides. Furthermore, this peptide motif demonstrated inhibitory effects on Aβ aggregation and dissociation. Upon immobilization of the peptide motif, Aβ aptamer-CdS QDs were bound to the electrode surface through peptide-specific interactions with Aβ, thereby facilitating the highly sensitive ECL detection of Aβ. Under the optimal conditions, the proposed biosensor exhibited an Aβ detection range from 0.1 pM to 100 nM with a detection limit of 16.1 fM. As such, this innovative platform offers a straightforward approach to antifouling, quantification, and monitoring of Aβ concentrations in the blood samples.

Performance Enhancement of Proton Exchange Membrane Fuel Cell through Carbon Nanofibers Grown In Situ on Carbon Paper

We developed an integrated gas diffusion layer (GDL) for proton exchange membrane (PEM) fuel cells by growing carbon nanofibers (CNFs) in situ on carbon paper via the electro-polymerization of polyaniline (PANI) on carbon paper followed by a subsequent carbonization treatment process. The CNF/carbon paper showed a microporous structure and a significantly increased pore volume compared to commercial carbon paper. By utilizing this CNF/carbon paper in a PEM fuel cell, it was found that the cell with CNF/carbon paper had superior performance compared to the commercial GDL at both high and low humidity conditions, and its power density was as high as 1.21 W cm-2 at 100% relative humidity, which is 26% higher than that of a conventional gas diffusion layer (0.9 W cm-2). The significant performance enhancement was attributed to a higher pore volume and porosity of the CNF/carbon paper, which improved gas diffusion in the GDL. In addition, the superior performance of the cell with CNF/carbon paper at low relative humidity demonstrated that it had better water retention than the commercial GDL. This study provides a novel and facile method for the surface modification of GDLs to improve the performance of PEM fuel cells. The CNF/carbon paper with a microporous structure has suitable hydrophobicity and lower through-plane resistance, which makes it promising as an advanced substrate for GDLs in fuel cell applications.

Continuous long-term glucose biosensor in agitation condition for bioconversion processes

The use of a glucose biosensor in the bioconversion processes is challenging due to a long period of intensive stirring that is required to mix the heterogenous substants together. In this work, a glucose biosensor was developed to be accurate and robust for an extended period of measuring time in agitated conditions. The sensor probe was fabricated by electro-polymerization of polyaniline (PANI) nanostructures on a gold wire before putting in gold nanoparticles (AuNPs) and carrageenan (carr) solution to make an PANI-carr-AuNPs layer. Then the probe was soaked in PQQ-Glucose dehydrogenase (GDH) solution before coating with polyurethane (PU) to prevent the enzymes from leaching away from the sensor. The sensor probe showed a sensitivity of 0.85 μA/mg/ml of glucose with R2 of 0.9973. The storage stability of the probe was up to 4 days with stable signal. In agitated condition of 150 rpm, steady signals from the sensor were continuously obtained for 72 h. In sugarcane bagasse hydrolysis with speed at 150 rpm for 72 h, the biosensor continuously displayed signals which were not significantly different in glucose concentration to the results from the HPLC method. This biosensor displayed promising applications in bioconversion processes.

PANI-Based Stacked Ferromagnetic Systems: Electrochemical Preparation and Characterization

In this work, the electropolymerization of polyaniline (PANI) is explored for its action as either a suitable coating or as a substrate for Nickel (Ni) and Magnetite (Fe3O4) surfaces. PANI electropolymerization has been achieved through cyclic voltammetry (CV), potentiostatic and galvanostatic electrochemical methods. The interaction between the obtained surfaces and the ferromagnetic layers (Ni and Fe3O4) has been investigated as a function of the pH of the electrolytic PANI solution, and also a variety of experimental parameters have been optimized in order to achieve the synthesis of PANI coatings (solvent, substrate, concentrations, and cell set-up). Thus, we obtained stable and consistent PANI thick films at the interface of both the nickel and the magnetite ferromagnetic materials.

Farklı Elektropolimerizasyon Koşulları Kullanılarak Hazırlanan Polianilin ile Elektrokimyasal Biyosensör Geliştirilmesi

Because of its excellent electrochemical properties, extreme redox performance, and ability to mediate the electron transfer between the electrode surface and the reaction site, polyaniline (PANI) is one of the most ideal and well-known conductive polymers for biosensor design. This research developed an electrochemical enzymatic biosensor system with PANI film-coated screen printed electrodes (SPE) using the one-step direct electropolymerization process. PANI electropolymerization was performed in different acidic solutions, and the effects on the electrodeposition of the potential range, potential scan rate, and cycle number are discussed depending on these acidic solutions. The surface morphologies of films prepared with different processes were characterized by usıng the SEM (scanning electron microscopy) technique. A sensitive and selective catechol biosensor was developed by immobilizing the tyrosinase (Tyr) enzyme into PANI film combined with glutaraldehyde as a cross-linking agent. After optimizing the biosensor performance conditions, the developed biosensor measured catechol in green tea samples.

The Performance of Polyaniline Electropolymerization at Various Acidic Electrolytes on Gold Electrodes for Electrochemical Biosensor Application

Polyaniline (PANI), a conductive polymer, has been played a significant role as an electrode material for electrochemical biosensor development. In this study, the electrochemical properties of PANI synthesized in two different acid dopants, i.e. 1.0 M HCl and 0.50 M H2SO4using chronopotentiometry, were investigated. The surface morphologies of the PANI modified gold electrodes were observed using SEM and EDS. The PANI electrodeposition times were also considered. The electrochemical characteristics in terms of the peak-to-peak potential separations (ΔEp), the current of the oxidation (Ipa), and reversible redox properties were investigated using cyclic voltammetry. The results showed that the modified electrode with PANI electropolymerization in H2SO4 as a dopant performed significantly better electrochemically than PANI in HCl at all electrodeposition times. In particular, the PANI prepared in H2SO4 with the electrodeposition time of 120 s demonstrated the best performance in terms of electron transfer and reversible redox reaction.

Electropolymerization investigation of polyaniline films on ITO substrate

In this work, the study of the electrodeposition of polyaniline (PANI) on Indium Tin Oxide (ITO) substrate by cyclic voltammetry and chronoamperometry from an acidic medium (0.5 M H2SO4 + 0.01 M Aniline + 0.1 M Na2SO4) revealed that the PANI electropolymerization is a quasi-reversible reaction controlled by the diffusion process.The electrochemical performances investigation using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge methods demonstrated that the PANI electrodeposited film is a pseudocapacitive material. The higher specific capacitance is about 21.76 mF cm−2 at a scan rate of 10 mV s−1, this value decreases increasing the scan rate. Similarly, the charge-discharge curves showed a specific capacitance of 9 mF cm−2 at 0.1 A cm−2.

Electropolymerization of polyaniline as high-performance binder free electrodes for flexible supercapacitor

Polyaniline (PANI), as one of the most promising electrode materials for flexible supercapacitors, faces the problems of limited capacitive behavior and poor cycling stability. Herein, we demonstrated that dopants have a great effect on the electrochemical performance of PANI. Selecting a suitable dopant can be used as an effective way for enhancing the electrochemical performance of PANI electrodes. All PANI electrodes were synthesized by electropolymerization method using hydrochloric acid (HCl), perchloric acid (HClO4), sulfuric acid (H2SO4), p-toluenesulfonic acid (p-TSA), phosphoric acid (H3PO4) and phytic acid (PA) as dopants, respectively. The influence of dopants on morphology, doping level, redox sites accessibility and electrochemical performance of PANI electrodes were studied systematically. The results show that, PANI/HClO4 has the best capacitive behavior with a maximum specific capacity of 1341 C g−1 at 5 mV s−1 along with a 57% capacity retention after 2000 cycles. Moreover, PANI/p-TSA shows the best cycling stability with 70% of capacity retention after 2000 cycles accompanied with a relatively high specific capacity (722 C g−1 at 5 mV s−1). Furthermore, PANI/HClO4 and PANI/p-TSA were used as electrodes for the fabrication of flexible all-solid-state symmetric supercapacitors. Results indicate that PANI/HClO4 device has higher energy density (12.57 Wh kg−1 at 283 W kg−1) than that of PANI/p-TSA (8.86 Wh kg−1 at 199 W kg−1). In contrast, PANI/p-TSA device with a capacity retention over 80% after 3000 cycles has better stability than PANI/HClO4 device which maintains 73% capacity after 3000 cycles. This fundamental study provides a much easier route in achieving high performance flexible PANI-based electrodes and opens new opportunities for facilitating PANI-based electrodes as promising candidates for wearable electronics.

Electro-polymerization of polyaniline on CVD grown transferrable vertically aligned CNT forest and its application in resistive detection of relative humidity

The article addresses the synthesis of vertically aligned MWCNT (VCNT) by chemical vapour deposition (CVD) process and deposition of a layer of polyaniline (PANI) by the electro-polymerization technique in a low-cost two-electrode cell using the VCNT as a cathode. The electro-deposition of PANI is carried out at three different times (10 min, 20 min, 30 min). A fruitful study on humidity sensing application has been shown here with the bilayer configuration of VCNT/PANI device. The morphological property of the device has been studied with field emission scanning electron microscopy (FESEM) images. For the growth confirmation of carbon nanotube, Raman spectroscopy is performed. The semi-crystalline microstructure and optical absorption properties of PANI have been investigated with X-ray diffraction and ultraviolet visible spectroscopy (UV–VIS).

A Correlative Study of Polyaniline Electropolymerization and its Electrochromic Behavior

The electrochemical polymerization of polyaniline (PANI) was studied using correlative measurements of electrochemistry and UV–vis spectroscopy, i.e., spectroelectrochemistry. The electropolymerization of PANI was performed in an acidic medium (1 M HCl) containing 0.1 M aniline with cyclic voltammetry (CV) in a potential window from −0.3 to 1 V and a 50 mV s−1 scan rate. At the same time, UV–vis absorbance spectra in the wavelength range from 200 to 900 nm were measured for every 10 mV change in the CV. The CV results show the oxidation of the monomer at a high positive potential (0.9 V vs Ag), the continuous growth of the PANI film and the transformation between the three best-known forms of PANI redox in the potential range between −0.3 V and 1 V. In parallel, the spectroscopic study confirmed the formation of PANI oxidation. The spectroscopic results showed the formation of the final conductive PANI product (emeraldine salt) due to the absorbance of the formed charge carriers (polarons, bipolarons) during the polymerization. The correlative electrochemical/spectroscopy study gave an additional dimension to the PANI polymerization mechanism, where not only was the oxidation the lead type of reaction, but the reduction was also found to play an important role.

Laser-enabled fabrication of flexible and transparent pH sensor with near-field communication for in-situ monitoring of wound infection

The pH of the wound milieu can provide valuable information regarding wound condition as related to early diagnosis of infection. Existing devices for measurement of wound pH are often expensive with readout systems that require trained personnel, making them impractical for clinical or home usage. This work reports on the development of a low-cost smartphone-based pH sensing platform that consists of a disposable, flexible, and transparent pH sensor interfaced with a custom-designed flexible, battery-less, and reusable near-field communication tag. The fabrication of the disposable potentiometric pH sensor, combines low-cost screen-printing with electro-polymerization of polyaniline on transparent electrodes that are fabricated by direct laser scribing of indium tin oxide (ITO) films. The sensors have a high sensitivity of −55 mV/pH within the physiologically relevant range of pH 4–10, with optical transparency to enable visual inspection of the underlying tissue. The sensor was demonstrated to successfully monitor pH changes in simulated in vitro wound conditions infected with gram-positive Staphylococcus epidermidis, as a proof-of-concept towards future use in vivo. Biocompatibility of all the materials used in the sensor was confirmed with dermal fibroblast cells (Clone B52).

Enhanced Electrocatalytic Activity of Cu2S-Polyaniline Heterostructure Counter Electrode for Quantum Dot-Sensitized Solar Cells

The Cu2S-Polyaniline (Cu-P) counter electrode (CE) was prepared by electropolymerization of polyaniline (PANI) on a FTO/Cu2S film. The surface morphology and crystallinity of the counter electrode were examined. The FTO/Cu-P CE provided significantly enhanced electrochemical activity and a faster charge transfer rate compared to the platinum (Pt), Cu2S, PANI, and PANI-Cu2S (P-Cu) CEs because of the synergistic effect between the high carrier mobility of PANI and the good electrocatalytic activity of Cu2S on the polysulfide electrolyte. Besides, the FTO/Cu-P CE exhibited excellent electrochemical stability, due to the strong interaction between the metal particles and electronegative nitrogen of PANI. The quantum dot-sensitized solar cell (QDSSC) with the FTO/Cu-P heterostructure CE exhibited a higher energy conversion efficiency (4.12%) than those with Pt (1.85%), Cu2S (3.71%), PANI (0.77%), and PANI-Cu2S (P-Cu) (1.01%) CEs.

Multi walled carbon nanotube and polyaniline coated pencil graphite based bio-cathode for enzymatic biofuel cell

In the present work, two types of cost-effective bio-electrodes were fabricated by immobilizing Laccase on commercially available pencil graphite leads, and their electro catalytic activity have been examined. The first type of electrode (E1) was fabricated by electro polymerization of polyaniline on pencil graphite leads on which multi walled carbon nanotubes (MWCNT) was immobilized by covalent bonding, while the second type of electrode (E2) was fabricated by direct coating of MWCNT on pencil graphite leads. Two types of bio-cathodes were fabricated by immobilizing Laccase on the two types of electrodes by covalent bonding. The scanning electron microscopy (SEM) revealed three dimensional porous networks providing large surface area for enzyme immobilization. The maximum open circuit potential (OCP) for E1 and E2 bio-cathodes were measured 0.58 V and 0.60 V respectively vs Ag/AgCl reference electrode. The maximum current density observed for E1 and E2 electrodes were 295.7 μAcm−2 and 228.94 μAcm−2 respectively. Both electrodes exhibited excellent stability, conserving more than 75% of its optimum activity during the period of measurement.

Coating of gold substrates with polyaniline through electrografting of aryl diazonium salts

The results of an experimental study on electrochemical preparation of polyaniline (PANI)/polycrystalline gold composites are reported in this work. A three steps approach is adopted in order to obtain a stable and uniform coating: (1) functionalization of the gold surface by 4-nitrophenyl group, (2) electrochemical reduction of the nitro group to amine, and (3) electropolymerization of aniline onto the surface of the aminophenyl-modified gold electrode. Cyclic voltammetries and electrochemical impedance spectroscopies are used to characterize the gold surface after each step. Also the results of a sample prepared by electropolymerization of PANI on bare gold are presented as a comparison.

Effect of Magnetic Field on the Electropolymerization and Corrosion Properties of Polyaniline (PANI) Film

The polyaniline have been prepared in the absence and presence of magnetic field by the technique of cyclic voltammetry (CV) on 304-stainless steel electrode in H2SO4 aqueous solution of aniline (Ani). The influence of magnetic field on electropolymerization of PANI was investigated by electrochemical properties, FT-IR spectra, X-ray diffraction (XRD) and microstructure. The results indicate that the effect of magnetic field on the polyaniline is positive.

Electropolymerization of polyaniline on titanium oxide nanotubes for supercapacitor application

Vertically aligned polyaniline (PANI) nanotubes have great potential application in supercapacitor electrode material. In this paper we have investigated facile growth of PANI nanotubes on a titanium nanotube template (TNT) using electrochemical polymerization. The morphology of PANI nanostructures grown over TNT is strongly influenced by the scan rate in the electrochemical polymerization. The growth morphology of PANI nanotubes has been carefully analyzed by field emission scanning electron microscopy. The detailed growth mechanism of PANI nanotubes has been put forward. Specific capacitance value of 740 F g −1 was obtained for PANI nanotube structures (measured at charge–discharge rate of 3 A g −1).