Modification Of Polyaniline Research Articles

Highly selective ratiometric electrogenerated chemiluminescence assay of DNA methyltransferase activity via polyaniline and anti-fouling peptide modified electrode

In this work, an antifouling electrochemiluminescent (ECL) ratiometric biosensor is designed for the accurate, selective and sensitive detection of DNA methyltransferase (MTase) activity based on a dual-signaling strategy. Briefly, an ITO electrode is used to construct the anti-fouling interfaces with the modification of polyaniline (PANI), AuNPs and peptide. Hairpin DNA molecules containing the symmetric sequence of 5′-CATC-3′ are attached onto the modified ITO electrode and the ds-DNA can be cut off in the presence of Dam MTase and DpnI. The residual DNA and two hairpin DNA could lead to the extension of ds-DNA due to the Hybridization Chain Reaction (HCR). ECL signal is amplified significantly with the insertion of PTC-NH2 molecules into the dsDNA grooves. The ECLPTC-NH2/ECLAu@luminol is found in a logarithmic linear relation with the concentration of Dam MTase. Moreover, owing to the presence of antifouling peptide on the sensing interface, the ECL biosensor was capable of sensing MTase activity in complex biological media, such as FBS samples and human serum with significantly reduced nonspecific adsorption effect. Assaying Dam MTase in complex sample mixture containing 5% calf serum and 5% human serum further proved the feasibility of this ECL biosensor for early clinical diagnosis.

Polyaniline sensitized Pt@TiO2 for visible-light-driven H2 generation

Polyaniline is a typical conducting polymer with high migration electron rate, good stability, eco-friendly properties, and high absorption coefficients for visible light. In the present study, polyaniline decorated Pt@TiO2 for visible light-driven H2 generation is reported for the first time. The above-mentioned nanocomposite is prepared through a simple oxidative-polymerization and characterized by infrared spectroscopy, transmission electron microscopy, X–ray diffraction, thermogravimetric analysis, and ultraviolet–visible diffuse reflectance spectra. Polyaniline modification improves the absorption of the nanocomposite in visible light region via a photosensitization effect similar to dye–sensitization but does not influence the crystal structure and size of Pt@TiO2. The polyaniline modified Pt@TiO2 exhibits a remarkable visible light activity (61.8 μmol h−1 g−1) and good stability for H2 generation (with an average apparent quantum yield of 10.1%) with thioglycolic acid as an electron donor. This work provides new insights into using conducting polymers, including polyaniline, as a sensitizer to modify Pt@TiO2 for visible-light hydrogen generation.

Failure behaviour of an epoxy coating with polyaniline modified graphene oxide under marine alternating hydrostatic pressure

Polyaniline (PANI) was used to modify the graphene oxide (GO) by in-situ polymerization. The failure behaviour of epoxy resin-based GO-PANI coating under marine alternating hydrostatic pressure (AHP) was investigated. The results indicated that PANI modification improves the dispersion of GO sheets and reduces the formation of initial surface defects, both of which significantly increase the compactness and mechanical properties of the coating. The improvement of the pigments/binder interface retards the diffusion of electrolyte and the deterioration of coating structure caused by AHP. The excellent anti-permeability of coating not only depends on the improvement of compatibility between GO and binder, but also the superior toughness provided by GO-PANI nanosheets.

Influence of carbon coating and PANI modification on the electrochemical performance of Li4Ti5O12

The Li4Ti5O12/polyaniline and Li4Ti5O12/С/polyaniline composite materials with different lithium titanate/aniline ratio of 8:1, 4:1, 2:1, 1:1, 1:2, and 1:4 were synthesized by in situ polyaniline (PANI) polymerization. The materials were characterized by high-resolution TEM, X-ray powder diffraction, IR spectroscopy, and TGA. It was shown that polyaniline is uniformly distributed over the surface of Li4Ti5O12 or Li4Ti5O12/С composite. For the sample with the minimum polyaniline content (Li4Ti5O12/С/PANI (8:1)), the PANI layer thickness is 2–3 nm and contains polyaniline in the most conductive (emeraldine) form. The lithium titanate modification with polyaniline results in sharp increase in the electronic conductivity of materials from ~ 10−11 Ohm-1 cm−1 for Li4Ti5O12 to 10−4 Ohm-1 cm−1 for Li4Ti5O12/C/PANI. With increasing polyaniline content, the electrochemical capacity decreases for all samples, including carbon-coated and uncoated ones. The highest discharge capacity at current density < 800 mA g−1 is attained for the Li4Ti5O12/С/PANI (8:1) composite.

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

Platinum nanoparticles deposited nitrogen-doped carbon nanofiber derived from bacterial cellulose for hydrogen evolution reaction

The nitrogen-doped carbon nanofiber derived from low and high proportion polyaniline doped bacterial cellulose (BC) was obtained via polymerization followed by pyrolysis. The resulting products were named LN-BC and HN-BC accordingly. Platinum nanoparticles modified LN-BC and HN-BC was then prepared (Pt@LN-BC and Pt@HN-BC) via electrochemical deposition. The morphologies of LN-BC and HN-BC indicated that the BC lost its nanowire structure after polyaniline modification and pyrolysis under nitrogen atmosphere. Platinum nanoparticles with diameters ranging from 3 to 5 nm can be well dispersed in the HN-BC support. The HER performance of Pt@LN-BC and Pt@HN-BC was fully investigated. Electrochemical results showed that the Pt-based catalysts had better HER activity than the Pt free catalysts in acid, indicating the HER activity was mainly from Pt. Besides, Pt@HN-BC had better HER activity than Pt@LN-BC in acid, suggesting N-doping rate was an important factor in enhancing HER activity. And the 10Pt@HN-BC (deposition for 10 s) with 4.38 wt% Pt loading was the best HER catalyst among the Pt@HN-BC. The onset potential (@ −1 mA cm−2) and overpotential (@ −10 mA cm−2) of the 10Pt@HN-BC in 0.5 M H2SO4 is −18 and −47 mV, respectively. The corresponding Tafel slope was −35 mV dec−1, which is quite comparable to that of Pt/C (10 wt%). The electrochemical double layer capacitance (Cdl) and turnover frequency (TOF) were estimated and presented in the work. Long-term stability test confirmed that the 10Pt@HN-BC had excellent stability, which was important for practical application.

Preparation of high strain polyaniline/polyvinyl alcohol composite and its applications in stretchable supercapacitor

Polyaniline (PANI) is one of the most extensively used conductive polymers. But its development and application has been restricted owing to the poor mechanical properties. Here, PANI/polyvinyl alcohol (PVA) composite with improved mechanical performance was prepared by mixing PANI hydrogel and PVA hydrogel. Due to excellent stretching capacity, it can be used as the electrode material for the high strain energy storage device. Therefore, a high strain all-solid-state PANI/PVA supercapacitor was further assembled by this flexible composite. The supercapacitor exhibits a high specific capacitance and excellent electrochemical stability even under tensile strain and over multiple stretching cycles. Meanwhile, the effect of stretching on the electrochemical properties was explored through theoretical simulation analysis and simulation calculation. This study could provide a theoretical reference for the modification of PANI and designing the scalable supercapacitor.

Facile fabrication of superhydrophobic polyaniline structures and their anticorrosive properties

ABSTRACTWe report a simple approach for the preparation of superhydrophobic polyaniline (PANI) and its application for the corrosion protection coatings. First, PANI was synthesized conventionally by oxidative polymerization with APS. Subsequently, PANI with different wettability was obtained by modification with different surfactants. The surface modification of PANI with three different surfactants (sodium dodecylbenzenesulfonate, polyethylene glycol, and cetyltrimethylammonium bromide) provided excellent surface superhydrophobicity (water contact angle &gt;150°). The structure and morphology of as‐prepared PANI were characterized with Fourier transform infrared, Energy dispersive X‐ray spectroscopy, and Scanning electron microscopy. Corrosion protection performance of PANI with different wettability was evaluated in 3.5% NaCl electrolyte using Tafel polarization curves and electrochemical impedance spectroscopy. The results indicated that various superhydrophobic PANI coatings have better anticorrosion performance as compared to the hydrophilic PANI. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44248.

Organic functionalization of thermally reduced graphene oxide nanoplatelets by adsorption: structural and morphological characterization

Adsorption of chlorinated poly(ethylene-co-vinyl acetate)-g-maleic anhydride copolymer and in situ-generated polyaniline (PANI) on thermally reduced graphene oxide (TRGO) platelets was studied in the current study. The adsorption was characterized structurally and morphologically through thermogravimetric analysis, differential scanning calorimetry (DSC), elemental analysis, infra-red and Raman spectroscopy, X-ray diffraction and microscopy. The amount of copolymer adsorption reached a plateau of 0.22 g per g of TRGO, when the initial copolymer to TRGO weight ratio of 1 was used. In the case of PANI modification, much higher extent of adsorption of 0.92 g/g of TRGO (without reaching plateau) was observed due to in situ polymer synthesis and the absence of any steric hindrance to the chains. Shift in the DSC melting transition temperatures of copolymer also indicated that some change in the polymer chain morphology took place after immobilization of polymer on TRGO. PANI modification led to significant reduction in peak melting point from 175C to 140 °C owing to the hindrance in polymer crystallization. The basal plane spacing in the TRGO platelets increased the copolymer adsorption as the 0 0 1 basal plane diffraction shifted from 27° 2Θ for pristine TRGO to 22.5° 2Θ for modified TRGO. For the PANI modified TRGO, no diffraction signal corresponding to TRGO was observed due to extensive adsorption of polymer on the surface. A much thicker polymer phase wrapping the TRGO platelets was observed for PANI modified TRGO. This was also observed through EFTEM and EDX, where the presence of Cl and N (along with other atoms) indicated layer of copolymer and PANI, respectively on the surface of the platelets. EELS analysis also confirmed the semi-crystalline nature of the modified TRGO resulting from the adsorption of semi-crystalline polymers on TRGO. The adsorption approaches used in the study demonstrate successful generation of the functional nanomaterials with tunable extent of surface coverage and potential of employing diverse surface modifications.

Polyaniline modification and performance enhancement of lithium-rich cathode material based on layered-spinel hybrid structure

The spherical lithium-rich cathode material with a layered-spinel hybrid structure is successfully synthesized and coated by polyaniline (PANI). The spherical material with layered-spinel hybrid structure is firstly prepared via the hydrothermal method, and then the conducting PANI is coated on the surface of the as-prepared spherical particle through an in-situ polymerization. Based on the analysis of scanning electron microscope (SEM), transmission electron microscope (TEM), high rate transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), it can be found that the size distribution of the spherical particles modified by PANI are about ∼1 μm, meanwhile the average thickness of the PANI layer on the surface of each particle is about 6.3 nm. The electrochemical performance of the spherical lithium-rich cathode material modified by PANI is apparently improved, the capacity retention is still 92.4% after 200 cycles at a rate of 0.5 C. The discharge capacities at 0.1 C and 10 C are as high as 302.9 mAh g−1 and 146.2 mAh g−1, respectively. Therefore, the modification of PANI for the spherical lithium-rich cathode material with a layered-spinel hybrid structure will be a promising technical route for the application with high capacity, long cycle life and good safety.

A Very Thin Layer of NiO, Ni(OH)&lt;sub&gt;2&lt;/sub&gt; Nanosheets Arrays with Organic Functional Modification of Polyaniline

NiO, conductive polymers have many important applications in supercapacitor, lithium-ion batteries, H2production with photocatalysis, chemical sensors, biosensors, electrochromic, environmental fields, and so on. Due to P-type semiconductors of NiO and polyaniline, the NiO/Polyaniline (PANi) would be a new nanocomposite with synergistic behaviors or complementary properties. Different morphologies of NiO were synthesized with hydrothermal method. NiO nanosheets arrays on glass substrate were obtained with optimized condition. And the NiO nanosheets arrays were immersed in the solution of aniline accompanying chemical oxidation reaction. The results indicated that a very thin layer of NiO, Ni (OH)2nanosheets arrays with organic functional modification of polyaniline were formed on glass substrate due to acid etching effects. The results of XRD showed that the presence of NiO and Ni (OH)2in prepared film were observed. The FTIR results also confirmed that this very thin film contained the components of polyaniline. This method is very simple, which would be used in many film electrodes for photocatalysis fields, supercapacitor, sensors, et al.

Controlled modification of carbon nanotubes and polyaniline on macroporous graphite felt for high-performance microbial fuel cell anode

Polyaniline (PANI) was electropolymerized on the surface of macroporous graphite felt (GF) followed by the electrophoretic deposition of carbon nanotubes (CNTs). The as-prepared macroporous material was characterized by scanning electron microscopy, water contact angle goniometry and electrochemical techniques. Upon the modification of PANI, a rough and nano-cilia containing film is coated on the surface of the graphite fibers, transforming the surface from hydrophobic to hydrophilic. The subsequent modification by CNTs increases the effective surface area and electrical conductivity of the resulting material. The power output of a mediator-free dual-chamber microbial fuel cell (MFC) constructed from the GF anode and an exoelectrogen Shewanella putrefaciens increases drastically with the CNT modification. The CNT/PANI/GF MFC attains an output voltage of 342 mV across an external resistor of 1.96 kΩ constant load, and a maximum power density of 257 mW m−2, increased by 343% and 186%, compared to that of the pristine GF MFC and the PANI/GF MFC, respectively. More bacteria are attached on the CNT/PANI/GF anode than on the PANI/GF anode during the working of the MFC. This strategy provides an easy scale-up, simple and controllable method for the preparation of high-performance and low-cost MFC anodes.

Cubic NiFe2O4 particles on graphene–polyaniline and their enhanced microwave absorption properties

Abstract The geometrical morphology of magnetic particles has an important influence on microwave absorption properties, but seldom researches have been focused on this issue. In this paper, cubic NiFe2O4 particles on graphene–polyaniline hybrid material were synthesized by a two-step method. TEM results show that most of NiFe2O4 particles have a cubic geometrical morphology. The investigation of the microwave absorbability reveals that the composites exhibit enhanced microwave absorption properties and wide absorption bandwidth. The maximum reflection loss is up to −50.5 dB at 12.5 GHz and the absorption bandwidths exceeding −10 dB are 5.3 GHz (from 11.0 to 16.3 GHz) with a thickness of 2.5 mm. The Cole–Cole plots demonstrate that there are multi-dielectric relaxation processes and the values of C0 indicate that the magnetic loss of the composites is mainly caused by natural resonance and eddy-current effects. Furthermore, our development strategies confirm that the surface modification of polyaniline and cubic NiFe2O4 particles on graphene makes the composites have a promising future in microwave absorption materials.

Perchlorate reduction in microbial electrolysis cell with polyaniline modified cathode

Excellent perchlorate reduction was obtained under various initial concentrations in a non-membrane microbial electrolysis cell with polyaniline (PANI) modified graphite cathode as sole electron donor. PANI modification is conducive to the formation of biofilm due to its porous structure and good electrocatalytic performance. Compared with cathode without biofilm, over 12% higher reduction rates were acquired in the presence of biocathode. The study demonstrates that, instead of perchlorate reduction, the main contribution of biofilm is involved in facilitate electron transfer from cathode to electrolyte. Interestingly, hairlike structure, referred as to pili-like, was observed in the biofilm as well as in the electrolyte. Additionally, the results show that pili were prone to formation under the condition of external electron field as sole electron donor. Analysis of microbial community suggests that perchlorate reduction bacteria community was most consistent with Azospiraoryzae strain DSM 13638 in the subdivision of the class Proteobacteria.

A Study on the Morphology, Mechanical, and Electrical Performance of Polyaniline-modified Wood - A Semiconducting Composite Material

This study investigated the morphology, electrochemical modification with respect to the wood fiber direction, and mechanical properties of wood modified by in situ polymerization with polyaniline (PANI). This polymerization formed a composite material with applications as an anti-static, electromagnetic, anti-corrosion, and heavy metal purifying materials. The polymer was found throughout the entire structure of the wood and was quantified within the wood cell wall and middle lamella by SEM-EDX. The presence of PANI affected the conductivity of the composite specimens, which was found to be higher in the fiber direction, indicating a more intact percolation pathway of connected PANI particles in this direction. The PANI modification resulted in a small reduction of the storage modulus, the maximum strength, and the ductility of the wood, with decreases in the properties of specimens conditioned in an environment above 66% relative humidity. The in situ-polymerized PANI strongly interacted with the lignin component of the veneers, according to the decrease in the lignin glass transition temperature (Tg) noted in DMA studies.

Fungal durability of polyaniline modified wood and the impact of a low pulsed electric field

New wood protection technologies should be effective against biodeterioration and at the same time minimize environmental impact. The present study investigates the effect of polyaniline modification of wood and the effect of a pulsed electric field on fungal protection. The effect of fungi and a pulsed electric field on the conductivity of the modified wood was also measured.It was found that it is possible to polymerize polyaniline particles in-situ homogeneously throughout the wood specimens. The polyaniline particles themselves were not found to be anti-fungal, however when in contact with water they affected the pH drastically and inhibited fungal growth. The wood treatment with polyaniline and the connection to a pulsed electric field were found to be effective in protecting the wood from deterioration when exposed to Postia placenta. The unmodified samples that were connected to a pulsed electric field lost under 10 wt% due to fungal degradation. The combination of polyaniline treatment with the connection to a pulsed electric field showed a slight synergistic effect which resulted in less weight loss due to fungal degradation. However, a more brittle wood structure was observed.Leached and fungal exposed samples showed a significant drop in the conductivity, indicating that the network has broken down slightly.

Preparation and Supercapacitor Performance of Nitrogen-Doped Carbon Nanotubes from Polyaniline Modification

Preparation and Supercapacitor Performance of Nitrogen-Doped Carbon Nanotubes from Polyaniline Modification

Chemical modification of polyaniline by N-grafting of polystyrenic chains synthesized via nitroxide-mediated polymerization

This study aims to explore an effective route for the preparation of conductive N-substituted polyaniline (PANI) by the incorporation of brominated poly(styrene-co-p-methylstyrene) onto the emeraldine form of polyaniline. For this purpose, at first, poly(styrene-co-p-methylstyrene) was synthesized via nitroxide-mediated polymerization (NMP), and then, N-bromosuccinimide was used as brominating agent to obtain a copolymer with bromine. Thereafter, deprotonated polyaniline was reacted with brominated poly(styrene-co-p-methylstyrene) to prepare the poly(styrene-co-p-methylstyrene)-graft- polyaniline [(PSt-co-PMSt)-g-PANI] terpolymer through N-grafting reaction. The terpolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Optical properties of (PSt-co-PMSt)-g-PANI in the undoped and doped states were obtained by ultraviolet-visible spectroscopy (UV-Vis), and electrical conductivity at room temperature was measured using samples in which the conductive materials was sandwiched between two Ni electrodes. Moreover, electroactivity of the synthesized terpolymer was verified under cyclic voltammetric conditions on the surface of the working glassy carbon electrode (GCE). The solubility of (PSt-co-PMSt)-g-PANI terpolymer was examined in common organic solvents, such as, tetrahydrofuran (THF), chloroform and xylene.

Inherently fluorescent polyaniline nanoparticles in a dynamic landscape

In this paper we report for the first time on the emissive behavior of two polyaniline (PANI) nanoparticle systems produced via oxidative chemical polymerization in the presence of either poly(vinyl alcohol) (PVA) or chitosan as polymeric stabilizers in water. The emission from PANI nanoparticles is irreversibly quenched by an increase of pH of the suspending medium from acid to neutral (chitosan–PANI) or alkaline (PVA–PANI). Conversely, PANI nanorods synthesized in the same conditions of the above, but in presence of poly(N-vinyl pyrrolidone), is not emissive at any pH. The role of the polymeric surfactant as a soft template is key in controlling the morphology and the properties of the obtained PANI dispersions. FTIR, UV–Vis absorption and photoluminescence excitation (PLE) spectra studies suggest that the emissive properties are related to the establishment of strong, non-covalent interactions between nanoscalar PANI particles and the polymeric surfactant at the pH of synthesis. Morphology examination of the three systems, by both dynamic light scattering (DLS) and Transmission Electron Microscopy (TEM), reveal that photoluminescence is associated to the presence of a genuinely 3D nanoscalar morphology, together with an ordered disposition of PANI chains into aligned crystal planes. Concomitant to the irreversible quenching of the emission signal with increasing pH, there is an evolution of the morphology leading to particle coalescence, coarsening and ultimately phase-separation, with consequent modification of PANI–polymeric surfactant interactions, PANI chains supra-molecular organization and optical properties of the PANI nanoparticles dispersion.

Power production enhancement with a polyaniline modified anode in microbial fuel cells

In this paper, an approach of improving power generation of microbial fuel cells (MFCs) by using a HSO4− doped polyaniline modified carbon cloth anode was reported. The modification of carbon cloth anode was accomplished by electrochemical polymerization of aniline in 5% H2SO4 solution. A dual-chamber MFC reactor with the modified anode achieved a maximum power density of 5.16Wm−3, an internal resistance of 90Ω, and a start-up time of 4 days, which was respectively 2.66 times higher, 65.5% lower, and 33.3% shorter than the corresponding values of the MFC with unmodified anode. Evidence from X-ray photoelectron spectroscopy and scanning electron microscopy results proved that the formation of biofilm on the anode surface could prevent the HSO4− doped polyaniline to be de-doped, and the results from electrochemical tests confirmed that the electrochemical activity of the modified anode was enhanced significantly after inoculation. Charge transfer was facilitated by polyaniline modification. All the results indicated that the polyaniline modification on the anode was an efficient approach of improving the performance of MFCs.