Chemical Oxidative Polymerization Of Aniline Research Articles

Study of Effect TiO2 Thin Film Morphological on Polyaniline/TiO2 Solar Cell Efficiency

In this work study preparation, structural, optical and electrical properties of polyaniline (PANi), nanocrystalline TiO2 and PANi: TiO2 nanocomposites. The TiO2 powder of particle size 50-60 nm was synthesized by sol-gel technique and the polyaniline was synthesized by chemical oxidative polymerization of aniline. The composite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and UV-Vis spectroscopy and the results were compared with polyaniline films. The intensity of diffraction peaks for PANi: TiO2 composites are lower than for TiO2. The characteristic FTIR peaks of PANi were found shift to higher wave number in PANi: TiO2 composite. These observed effects have been attributed to interaction of TiO2 particles with PANi molecular chains.

Polyaniline-intercalated manganese dioxide nanolayers prepared by a delamination/reassembling process and its application for hydrogen peroxide sensing

In this study, polyaniline-intercalated MnO2 (PANI-MnO2) nanolayers were prepared by a delamination/reassembling process, in which the chemical oxidation polymerization of aniline and the reduction of MnO4− to MnO2 occur simultaneously. The morphology and chemical composition of the synthesized PANI-MnO2 were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy. A modified glassy carbon electrode based on PANI-MnO2 was designed as the electrochemical sensor for hydrogen peroxide. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry. The results showed that PANI-MnO2 had better electrocatalytic activity in the reduction of hydrogen peroxide than pure MnO2, with wide linear ranges at concentrations between 1.0×10−5 and 1.89×10−3 mol/L and between 1.89×10−2 and 30.89×10−2 mol/L, with high sensitivities of 33.4 and 57.6 μA/(mmol.cm2), respectively, and a satisfactory recovery rate of approximately 94.2–105%. Therefore, the prepared sensor can be a promising tool for the detection of hydrogen peroxide in real-life application.

Surface Modification of Cellulose Nanofiber with Polyaniline using Aniline Monolayer as Seed for Chemical Oxidation Polymerization of Aniline

A simple method is adopted to prepare conducting polyaniline thin film on cellulose filter paper by chemical oxidative polymerization. In order to improve the adhesion of polyaniline on cellulose nanofiber aniline terminal, silane monolayer was used as catalyst to initiate polymerization reaction. It was also showed that aniline dimer modified cellulose nanofiber shows an enhanced polyaniline growth and acting as seed for the polyaniline growth. The polyaniline modified cellulose fibre filter paper was then characterized with UV-visible spectroscopy, FT-IR, FE-SEM and electrochemical studies. Polyaniline modified filter paper strips can be used for naked eye sensing of ammonia and hydrazine in environmental samples

Synthesis of polyaniline (printable nanoink) gas sensor for the detection of ammonia gas

Here we are reporting the printable nanoink of polyaniline (PANI) which can be printed over the flexible substrate. The printed patterns (flexible) are used for the detection of toxic ammonia gas. The conducting polymer polyaniline (PANI) is synthesized by the chemical oxidative polymerization of aniline. The synthesized PANI is characterized by FTIR, UV–visible, XRD, FESEM and TEM. The FESEM and TEM micrograph shows the formation nanotubes of the PANI having the average diameter of 10.85 nm and average length of 45.6 nm. The XRD analysis revealed the PANI is between amorphous nature and crystalline. The synthesized PANI has the optical energy band gap of 2.9 eV. The printed pattern of PANI has able to detect the lowest concentration of 2.5 ppm of ammonia gas. It has the sensing response of 75%, with response time of 110 s and recovery time of 55 s at 2.5 ppm concentration. The sensor has the sensitivity of 1.0036 ppm−1.

Magnetic and electrically conductive silica-coated iron oxide/polyaniline nanocomposites for biomedical applications

This work describes the development of novel dual-stimuli-responsive nanocomposites based on silica-coated iron oxide/polyaniline (Si-MNPs/PANI) for biomedical applications. Si-MNPs/PANI nanocomposites were developed via chemical oxidative polymerization of aniline in the presence of Si-MNPs (25 and 50 wt%). Si-MNPs/PANI were obtained both in nanotubular (SPNTs) and granular (SGTs) forms by altering the synthesis parameters such as acid concentration and mixing process. The effects of nanocomposite morphology were evaluated by investigating their chemical, physical and biological properties. Material characterization was comparatively carried out via SEM, TEM, FTIR, XRD, TGA, room temperature VSM, and electrical resistivity measurements. Biological properties were evaluated by indirect in vitro cytotoxicity and in vitro hemocompatibility analyses according to ISO standards. Results indicated that Si-MNPs/PANI nanocomposites exhibited both magnetically and electrically-responsive properties. Magnetization values of Si-MNPs/PANI nanocomposites increased with increasing Si-MNPs content. However, electrical conductivity was inversely proportional to Si-MNPs content. In addition, SGTs represented remarkably higher electrical conductivity (1.1 S/cm) than SPNTs (4.8 × 10−2 S/cm), but lower saturation magnetization (21 emu/g) compared to SPNTs (27 emu/g). Furthermore, in vitro cytocompatibility and hemocompatibility of the SGTs and SPNTs varied in a dose-dependent manner, suggesting their use in certain doses for biomedical applications. In conclusion, the developed Si-MNPs/PANI, with magnetic sensitivity and electrical conductivity have potential as nanocomposites for utilization in biomedical applications, e.g. biosensing, controlled-drug delivery, bioelectronic systems, tissue engineering and regenerative medicine as active compound. Besides, the selection of the appropriate synthesis protocol allows Si-MNPs/PANI nanocomposites to exhibit superior properties according to the targeted application area.

Nano-flowered manganese doped ferrite@PANI composite as energy storage electrode material for supercapacitors

Herein, we report a 3D nanoflower MnFe2O4@PANI composite as electrode material in supercapacitor. Manganese doped ferrites were synthesized by hydrothermal method followed by in-situ chemical oxidative polymerization of aniline to form a nanoflower composite. The nanoscale MnFe2O4 were infused with polyaniline (PANI) that offer superior synergistic effects by favouring access to charge/ion transit route, which is further improved by providing a broad surface area that is electrochemically active. It is entrenched that MnFe2O4@PANI involves charge transfer pseudocapacitance at both the ionic sites of Mn and Fe and oxidized emeraldine salt of PANI, balanced by the inclusion/exclusion of proton within/outside the lattice. On the one hand, the fluffy nature of PANI provided channels for charge transport, and manganese ferrites helped in storing the electrons through changes in the valence state of the active sites. We obtained a high specific capacitance of 623 F/g at a current density of 1 A/g. A prototype of the developed supercapacitor showed excellent device performance with a high energy density of 179 Wh/kg and maximum power density of 982 W/kg with ~95% retention of specific capacitance after 10,000 cycles.

Nickel decorated melamine-formaldehyde resin/polyaniline composites for high specific capacitance

Nickel decorated electro-conducting melamine-formaldehyde resin (MFR) composites were prepared in two steps. In the first step micron-sized electro-conducting MFR/polyaniline (PAni) composite particles were prepared by in situ seeded chemical oxidative polymerization of aniline in presence of mesoporous MFR seed particles. Then surface of MFR/PAni composite particles were decorated/doped with Ni particles via in situ chemical reduction of Ni(II) salt. The size, chemical composition and magnetic properties of the prepared composite particles named as MFR/PAni/Ni were analyzed by scanning election microscope (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) surface analysis, Fourier Transform IR (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analyzer (TGA) and vibrating sample magnetometer (VSM). The results suggested that surface of MFR/PAni composite particles are best doped/decorated with Ni particles when MFR/PAni to Ni weight ratio was 1/0.1. An increase in Ni amount resulted in higher agglomeration and produced some free Ni particles. MFR/PAni/Ni composite particles possessed paramagnetic characteristics. The electrochemical/capacitive performance of MFR/PAni/Ni composite materials was evaluated by cyclic voltammetry (CV). Surface decoration/doping of MFR/PAni composite particles with increasing amount of Ni particles improved the specific capacitance value, suitable for application in supercapacitor.

Fabrication of Silica/Sulfur@Polyaniline Spheres with Radial Mesochannels as Enhanced Cathode Materials for High‐Performance Lithium−Sulfur Batteries

AbstractThe unique structure SiO2/S@polyaniline (PANI) composite with radial meso‐channels was designed and synthesized by in situ chemical oxidative polymerization of aniline on SiO2/S surface. The composite was used as the cathode for lithium−sulfur batteries. The SiO2 nanospheres with radial meso‐channels provided sufficient internal space to accommodate the volume expansion for sulfur and possessed strong adsorption capability for lithium polysulfides (LiPSs). Additionally, the thin PANI coating serving as conductive frameworks generated sufficient electrical conduction paths and effectively prevented the outward diffusion of LiPSs, leading to long‐term stability. Benefitting from the composites’ unique structural and compositional advantages, we obtained an initial specific capacity of 1008.6 mA h g−1 at 0.2 C and an outstanding cycling stability at 1 C rate over 1000 cycles with a capacity decay of 0.04% per cycle. An excellent rate performance of 630.2 mA h g−1 at 2 C was also achieved. Our work reveals the potential application of the porous SiO2@PANI‐based sulfur cathodes in future high‐performance lithium−sulfur batteries. Furthermore, first‐principle calculations and X‐ray photoelectron spectroscopy analysis prove the strong adsorption of LiPSs by the SiO2 surface. The formation of S−O bond on the SiO2 is also found to dominate the adsorption mechanism between LiPSs and SiO2.

New nitrogen-rich flame retardant based on conductive poly(aniline-co-melamine)

In the present work, a new copolymer was synthesized using aniline and melamine as a comonomer in order to increase the content of nitrogen in the final copolymer. The copolymer was synthesized via chemical oxidative polymerization of aniline and melamine, at different ratios, in the presence of ammonium peroxydisulfate (APS) as an oxidant. The obtained copolymers were characterized by Fourier-Transform Infrared spectroscopy (FTIR), Ultraviolet-visible (UV–Vis) spectroscopy, and Energy-dispersive X-ray (EDX). The solubility of the prepared copolymers was tested in various common organic solvents and the results showed that their solubility was better than polyaniline (PANI) in polar aprotic solvents. The elemental analysis revealed high content of nitrogen, around 72 wt% in one copolymer, against 34.6 wt% in the case of polyaniline homopolymer. The average conductivity of the PANI was 1.02 × 10−1 S/cm while it was between 6.1 × 10−4 S/cm and 2.9 × 10−2 S/cm for copolymers. Thermal degradation and flammability were investigated using Thermogravimetric analysis (TGA) and Pyrolysis Combustion Flow Calorimeter (PCFC), respectively. TGA results showed that the onset temperature of decomposition was significantly increased for all copolymers in respect to polyaniline. Moreover, PCFC tests revealed very low flammability character of the synthesized copolymers demonstrated by the Total Heat Release (THR) between 3 and 5 kJ/g. The elemental analysis of the remained char residue at the end of TGA showed that even at 900 °C, the high amount of nitrogen remained in the condensed phase for two copolymers.

Структурные, емкостные и энергетические характеристики электрохимических электродов на основе нанокомпозитов «полианилин/многостенные углеродные нанотрубки»

Polyaniline nanocomposites with nitrogen-doped multiwalled carbon nanotubes, initial and functionalized argon ions are prepared by the in-situ chemical oxidative polymerization of aniline. The morphology of obtained nanocomposites are studied by microscopic methods. The capacitive and energy characteristics of electrochemical electrodes formed by pressing nanocomposites have been studied by cyclic voltammetry. It is shown that an electrode based on a nanocomposite with functionalized nanotubes has the highest specific capacity and energy due to the high porosity of the surface. However, the low mechanical strength of this electrode leads to a decrease in its cyclic stability

Изучение процесса переноса заряда в гетеропереходе полианилин/графит методом проводящей атомно-силовой микроскопии

Thin layers of polyaniline on the surface of highly oriented pyrolytic graphite are obtained by in-situ chemical oxidative polymerization of aniline. The current-voltage characteristics of the tip/polyaniline/graphite contact, which have a form characteristic of tunnel contacts, have been measured by the method of conducting atomic force microscopy. By modeling the current-voltage characteristics using the Simmons model, the width of the potential barrier is determined, which for the investigated heterojunction is 0,5 nm

Fabricating electronic textile using nano MnO2/polyaniline composites for capacitor device

In this study, cotton fabric was employed to achieve electronic textile by incorporating nano MnO2 and polyaniline as conductive materials. The treatment was accomplished via two consecutive steps, where different concentrations of MnO2 were initially applied by the ultrasound-assisted template method onto the cotton samples to synthesize nanoMnO2. The nano form of the metal oxides and polyaniline inclusion were demonstrated through a transmittance electron microscope. Thereafter, chemical oxidative polymerization of aniline over the nano metal oxide–loaded fabrics was performed. Structure, phase, and purity of as-treated fabrics were determined using X-ray diffraction and Fourier transform infrared spectroscopy. The thermal properties of the fabricated conductive samples were also tested. The electrical conductivity of the obtained (nano MnO2/polyaniline) modified cotton fabrics showed great enhancement by exposing the modified samples to gamma irradiation, as a posttreatment, to reach an optimum condition at 40 kGy, using 0.2 M MnO2. The recorded increment for electric conductivity was from 5.4 × 10−3 to 1.43 × 10−1 Ω−1. m−1 for both unirradiated and 40 kGy irradiated samples, respectively. Pseudo-capacitance of cotton/MnO2/polyaniline fabric electrode was tested using a three-electrode system. The assumption of (nano MnO2/polyaniline) cotton fabric conductivity was verified through a designed pseudo-capacitor as an important yet simple form of an energy storage device.

Formation of Polyaniline-MOF Nanocomposites Using Nano-Sized Fe(III)-MOF for Humidity Sensing Application.

Polyaniline (PA)-MOF nanocomposites have been successfully synthesized through an in-situ chemical oxidative polymerization of aniline in the presence of nano-sized iron trimestate (named as MIL-100(Fe)) particles, which was prepared by a microwave-irradiation method. Water sorption and humidity sensing results clearly showed that water sorption rate and humidity sensitivity are dramatically enhanced by the composites using nano-sized MIL-100(Fe) as compared with that using micrometer-sized MIL-100(Fe) particles.

Surface modification of poly (L-lactic acid) films to improve electrical conductivity by surface entrapment/in situ polymerization methods

Electrical properties play an important role in the interaction of cells and biomaterials. The aim of this study was to increase surface electrical conductivity of poly (L-lactic acid) (PLLA) films by polyaniline (PANI) using surface entrapment (SE) and surface entrapment in situ polymerization (SEIP) methods. The entrapment modification technique was performed by the reversible gelation of the PLLA surface region following exposure to a solvent and non-solvent mixture, while PANI chains were diffused into the swollen PLLA surface. In SEIP method, PANI was entrapped through in situ chemical oxidative polymerization of aniline on PLLA films. The effects of PANI concentration, the ratios of solvents and immersion time on the electrical conductivity were studied by SE method. The effects of aniline concentration, doping effect, temperature and time of polymerization were evaluated by SEIP method too. The results obtained by attenuated total reflection Fourier transformer infrared spectroscopy, scanning electron microscopy and energy dispersive x-ray mapping analysis confirmed the presence of PANI on the surface of PLLA films. UV-visible analysis was employed to investigate the doping effect on the reduction of energy and conductivity of the films. Experimental results also indicated that the electrical conductivity, uniformity and density of the SEIP modified films were significant in comparison to those of the modified films by SE method.

Highly Luminescent Ternary Nanocomposite of Polyaniline, Silver Nanoparticles and Graphene Oxide Quantum Dots

Quantum dots (QDs) with photostability show a potential application in optical sensing and biological imaging. In this work, ternary nanocomposite (NC) of high fluorescent polyaniline (PANI)/2-acrylamido-2-methylpropanesulfonic acid (AMPSA) capped silver nanoparticles (NPs)/graphene oxide quantum dots (PANI/Ag (AMPSA)/GO QDs) have been synthesized by in situ chemical oxidative polymerization of aniline in the presence of Ag (AMPSA) NPs and GO QDs. Ag (AMPSA) NPs and GO QDs were prepared by AgNO3 chemical reduction and glucose carbonization methods, respectively. The prepared materials were characterized using UV-visible, Fourier transform infrared (FTIR), photoluminescence and Raman spectroscopies, X-Ray diffractometer (XRD) and high- resolution transmission electron microscopy (HRTEM). HRTEM micrographs confirmed the preparation of GO QDs with an average size of 15 nm and Ag (AMPSA) NPs with an average size of 20 nm. PANI/Ag (AMPSA)/GO QDs NC showed high and stable emission peak at 348 nm. This PANI/Ag (AMPSA)/GO QDs NC can emerge as a new class of fluorescence materials that could be suitable for practical sensing applications.

ТЕРМІЧНИЙ АНАЛІЗ ПОЛІАНІЛІНУ ТА КОМПОЗИТІВ ЦЕЛЮЛОЗА/ПОЛІАНІЛІН, СИНТЕЗОВАНИХ У ВОДНИХ РОЗЧИНАХ ОРГАНІЧНИХ КИСЛОТ

The physicochemical properties of obtained composites and efficiency of deposition of polyaniline (PAn) on cellulose (Cel) surface depends on conditions of the reaction pf chemical oxidative polymerization of aniline (An), namely both the nature of acid-dopant and oxidant, the ratio of monomer/oxidant and An/Cel, temperature of synthesis, degree of dispersion and pre-treatment of Cel etc. Use as dopants the organic acids with different number of carboxylic groups enhances the chemical affinity of components in composites materials of cellulose/polyaniline (Cel/PAn).

Poly(4-vinylaniline)/Polyaniline Bilayer-Functionalized Bacterial Cellulose for Flexible Electrochemical Biosensors.

A bacterial cellulose (BC) nanofibril network is modified with an electrically conductive polyvinylaniline/polyaniline (PVAN/PANI) bilayer for construction of potential electrochemical biosensors. This is accomplished through surface-initiated atom transfer radical polymerization of 4-vinylaniline, followed by in situ chemical oxidative polymerization of aniline. A uniform coverage of the BC nanofiber with 1D supramolecular PANI nanostructures is confirmed by Fourier transform infrared, X-ray diffractogram, and CHN elemental analysis. Cyclic voltammograms evince the switching in the electrochemical behavior of BC/PVAN/PANI nanocomposites from the redox peaks at 0.74 V, in the positive scan and at -0.70 V, in the reverse scan, (at 100 mV·s-1 scan rate). From these redox peaks, PANI is the emeraldine form with the maximal electrical performance recorded, showing charge-transfer resistance as low as 21 Ω and capacitance as high as 39 μF. The voltage-sensible nanocomposites can interact with neural stem cells isolated from the subventricular zone (SVZ) of the brain, through stimulation and characterization of differentiated SVZ cells into specialized and mature neurons with long neurites measuring up to 115 ± 24 μm length after 7 days of culture without visible signs of cytotoxic effects. The findings pave the path to the new effective nanobiosensor technologies for nerve regenerative medicine, which demands both electroactivity and biocompatibility.

Polyaniline nanoparticle coated graphene oxide composite nanoflakes for bifunctional multicolor electrochromic and supercapacitor applications

Graphene oxide (GO)/polyaniline (PANI) composite nanoflakes were fabricated by chemical oxidative polymerization of aniline onto GO nanoflakes. The electrochromic properties and the electrochemical capacitive behaviors of the GO/PANI composite nanoflake film were investigated. The GO/PANI nanocomposite film exhibits excellent electrochromic and supercapacitive performances. In comparison with neat PANI film, the GO/PANI composite nanoflake film shows larger optical modulation, faster response speed, larger coloration efficiency and better cycling stability. Moreover, an areal capacitance of (137 mF/cm2) is obtained for GO/PANI nanoflake film at a scanning rate of 5 mV/s, higher than that of neat PANI film (36 mF/cm2). The GO/PANI composite nanoflake film also shows enhanced electrochromic and supercapacitive durability. And the electrochromism also could be utilized as an indicator for the capacitance. The high-performance GO/PANI nanocomposite film shows promising features for multifunctional devices combining energy storage and electrochromism.

Synthesis and characterization of polyaniline/BEA zeolite composites and their application in nicosulfuron adsorption

Composite materials of BEA zeolite and polyaniline (PANI) were prepared by the chemical oxidative polymerization of aniline in the presence of zeolite in water (without added acid) and in an aqueous solution of sulfuric acid, using ammonium peroxydisulfate as an oxidant. Protonated (as-synthesized) and deprotonated forms of the composites and pristine PANIs were characterized by scanning electron microscopy, conductivity and zeta potential measurements, FTIR, Raman and XPS spectroscopies, and thermogravimetric analysis. Adsorption properties of synthesized materials for removal of nicosulfuron pesticide from aqueous solutions were studied, using HPLC technique. The obtained adsorption isotherms were analyzed using Freundlich and Langmuir-Freundlich equations. Protonated PANI/BEA composites showed excellent adsorption capacity (18.4–25.4 mg g−1), that was higher than the adsorption capacity of pristine BEA zeolite (18.2 mg g−1) but slightly less than neat PANI. Among PANIs, the highest adsorption capacity of 29.8 mg g−1 of adsorbent was found for protonated PANI prepared in sulfuric acid solution. Analysis of adsorption isotherms revealed high degree of surface homogeneity for all prepared composite materials and PANIs. Proposed mechanism for enhanced adsorption of nicosulfuron on protonated composites is based on hydrogen bonding of nicosulfuron O- and N-containing groups with bridging hydroxyls of BEA zeolite and –NH/ = NH+/−NH•+ groups in protonated emeraldine salt form of PANI chains (PANI-ES), accompanied with electrostatic attractive interaction between anionic nicosulfuron species and positive = NH+/−NH•+ groups in bipolaron/polaron containing structures of PANI-ES. Presence of protons in bridging hydroxyls in BEA zeolite and in protonated PANI-ES chains is essential for excellent adsorption of nicosulfuron via hydrogen bonding on all protonated composite samples. In support of this interpretation, deprotonated PANI/BEA composites and deprotonated PANIs showed significantly lower adsorption capacities (in the range 5.5–13.0 mg g−1) compared to those of their protonated counterparts.

Mesoporous electromagnetic composite particles: Electric current responsive release of biologically active molecules and antibacterial properties

Electric current responsive magnetic composite particles are prepared in three steps. In the first step, spherical and mesoporous submicrometer-sized magnetic iron oxide (Fe3O4) core particles are prepared by solvothermal method. Then magnetic Fe3O4 particles are functionalized with amine groups using glycine, where the COO- group of glycine formed a bridging bidentate interaction with the hydroxyl groups on Fe3O4 particle surface. Finally polyaniline (PAni) is grafted onto the functional Fe3O4 surface via in situ seeded chemical oxidative polymerization of aniline. The average size of Fe3O4/PAni composite particles is 418.82 nm with mesoporous surface structure. Electron microscopic images confirmed that PAni pockets are localized on the surface of Fe3O4 core particles. The surface composition is further confirmed by Fourier transform IR (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimety (TG) analyses. Fe3O4/PAni composite particles possessed strong paramagnetic property (47.77 emu g−1). The electrical conductivity of Fe3O4/PAni composite particles (1.46 × 10-4 S cm−1) remained in the same order of magnitude as that of reference PAni particles (3.42 × 10-4 S cm−1). The release behavior of biologically active molecules such as trypsin (TR), albumin (AL) and p-acetamido phenol (pAP) is studied using low intensity electric current as stimuli to prevent degradation. Depending on the nature, up to ˜ 33–88% of adsorbed biomolecules/drug are released from the electromagnetic Fe3O4/PAni composite particles. Compared to Fe3O4 particles, Fe3O4/PAni composite particles exhibited moderate antibacterial property.