Chemical Synthesis Of Polyaniline Research Articles

Chemical synthesis of polyaniline and polythiophene electrodes with excellent performance in supercapacitors

The emergence of portable electronics in miniaturized and intelligent devices demands high-performance supercapacitors (SC) and batteries as power sources. For the fabrication of such energy storage devices, conducting polymers (CPs) have significant advantages due to their high theoretical capacitive performance and conductivity. In this work, we developed two CPs including polyaniline and polythiophene through a low-cost chemically synthesized approach and the film-by-spin coating method. The structural and morphological properties of the CPs are analyzed using Fourier-transform infrared spectroscopy (FTIR), contact angle measurement, and scanning electron microscopy (SEM). Based on these CPs, novel pristine polyaniline and polythiophene-based SCs (PASC and PTSC) are developed. The prepared CPs contribute to high electrochemical performances due to their high conductive nature of the electrode and conjugated polymer materials reaction. Hence both electrochemical double-layer formation and pseudocapacitance contributed to the energy-storing performances of the device. Electrochemical impedance spectroscopic analysis (0.1 Hz to 100 kHz) demonstrates faster ionic exchange and high capacitance of the PASC electrode as compared to PTSC in H3PO4 electrolyte. The PASC devices exhibit specific capacitance of 13.22 mF·cm−2 with energy and power densities of 1.175 μW·h·cm−2 and 4.99 μW·cm−2 at a current of 50 μA. Compared to PTSC (specific capacitance 3.30 mF·cm−2) the PASC shows four times higher specific capacitance due to its improved surface, structural and electrical properties. The electrochemical performance reveals the superior SC performance for this type of CP electrode.

Electrochemical Synthesis of Polyaniline and Its Anticorrosive Application: Improvement and Innovative Design of the “Chemical Synthesis of Polyaniline” Experiment

Electrochemical Synthesis of Polyaniline and Its Anticorrosive Application: Improvement and Innovative Design of the “Chemical Synthesis of Polyaniline” Experiment

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.

Study of methylene blue dye elimination from water using polyaniline (PANI) and PANI/SiO2 composite

Conducting polymeric composites have attracted great attention over the last years because of their potential uses in chemical, electronic and optical devices, and as catalysts as well as in adsorption processes. Chemical synthesis of polyaniline (PANI) and polyaniline-SiO2 composite and their adsorptive performance were reported in the present work. These materials were prepared and evaluated for their methylene blue (MB) dye adsorption characteristics from aqueous solution. Adsorption equilibrium kinetic and thermodynamic experiments of MB onto PANI and PANI/SiO2 were studied. The effects of initial dye concentration, contact time and temperature on the adsorption capacity of PANI/SiO2 for MB have been investigated. The pseudo-first order and pseudo-second order kinetic models were used to describe the kinetic data. It was found that adsorption kinetics followed the pseudo-second order at all of the studied temperatures. The Langmuir, Freundlich and Dubinin Raduschkevich adsorption models were used for the mathematical description and the HyperChem v8 software was exploited to propose a possible mechanism of the adsorption process.

Chemical Synthesis of Polyaniline and Its Composites with Iron, Nickel and Manganese Oxides for Applications in Supercapacitors

With the increase in energy consumption added to the risk of depletion of fossil fossils, the need for the development of renewable energy sources for energy storage increases, but these sources are limited due to the variation in availability. Thus, the development of devices that generate and store energy as supercapacitors is widely explored. One of the factors that influence the performance of supercapacitors is the choice of electrode material. They can have double layer capacitance or pseudocapacitive to charge storage systems.Among the materials with EDL capacitive nature, the carbon materials stand out, the carbon fibers (CFs), which have a large specific surface area, high pore accessibility and excellent thermal and chemical stability. In relation to pseudocapacitive materials, examples are conductive polymers (CPs), which combine electrical properties of semiconductors and metals with those of conventional polymers, such as simple preparation and metallic oxides (MOs), which have varying morphologies, high theoretical specific capacitance, in addition to abundant reserves.The materials mentioned above can improve their electrochemical performance when combined due to the synergistic effect. Thus, through the production of hybrid composites, it is possible to produce smaller devices with greater energy efficiency.In this work, the MOs used were Fe2O3, NiO and MnxOy, and the CP used was polyaniline (PANI). Composites of PANI / Fe2O3, PANI / NiO and PANI / MnxOy were obtained. The MOs were obtained via hydrothermal synthesis, and the CP and the composites, via chemical synthesis. These materials were characterized by FEG, FT-IR, XRD, Raman, EIS and CV.Through the analysis of FEG, it was possible to observe agglomerated and granular forms for PANI, which is in accordance with previous studies of chemical polymerization. Through the images of the composites, it is concluded that PANI coated the oxides. It is also observed that there are pores in the morphologies, a desired characteristic for supercapacitor electrode materials.From the FT-MIR spectra of the materials, it was observed that the synthesis was reproductive due to the similarity between them. However, for composites, there was a redshift in the absorption bands, corroborating the structure proposed by NANDAPURE et. al. in which the MO is involved by PANI, so that there is interaction with the imine group. In addition, new bands appeared at the end of the spectrum, related to the presence of metal oxides in the material. Through Raman spectroscopy, it was possible to observe characteristic bands of PANI in the materials spectra. There was an increase in the intensities of the composites bands, due to the interactions of hydrogen bonds between the oxide M-O group and the PANI imine group. The composites showed oxidation degrees closer to 0.5 compared to PANI, indicating a more conductive material.The X-ray diffractograms showed reflections characteristic of the MOs. PANI showed semicritalin nature, with characteristic halos and according to the literature, and they appeared in the diffractograms of the composites, reinforcing the idea of the polymer coating. In addition, the halos become narrower in the composites, favoring crystallinity, especially MnxOy. The materials were subjected to electrochemical analyzes in carbon fiber (CF). The analysis of Electrochemical Impedance Spectroscopy shows capacitive profiles of the synthesized materials with phase angle close to 90 in the regions of medium and low frequencies. In addition, low RTC values and low impedance modulus were observed.By Cyclic Voltammetry, redox peaks characteristic of leukosemeraldina and emerald transition were evidenced related to faradaic processes around 0.2 V and quinone-hydroquinone transitions close to 0.5 V in all materials. For composites, there was an increase in current density, related to the capacitive contribution. Figure 1

Influence of Electric Field during the Chemical Synthesis of Polyaniline on the Surface of Heterogeneous Sulfonated Cation-Exchange Membranes on the Their Structure and Properties

The influence of electric field in the chemical synthesis of polyaniline on the surface of sulfonated cation-exchange membranes on their structure and properties has been investigated. By using standard contact porosimetry, it has been found that surface modification of heterogeneous membranes with polyaniline, both in static conditions and in an external electric field, does not significantly affect the distribution of water over the effective pore radii and binding energies. It has been shown that the structural heterogeneity of the ion-exchange membrane, rather than the aniline polymerization conditions, has a more significant effect on the morphology of the polyaniline layer on its surface and, hence, on the electrotransport properties. A decrease in the electrical conductivity of the composites obtained with an increase in the quantity of electricity passed during the synthesis of polyaniline on their surface has been revealed. Based on the analysis of the current–voltage characteristics of the samples and their electrical conductivity, the conditions for obtaining materials with the most pronounced asymmetry of the electrotransport properties have been determined.

Facile and template‐free method toward chemical synthesis of polyaniline film/nanotube structures

ABSTRACTA facile and template‐free method is reported to synthesize a new thin film structure: polyaniline (PANI) film/nanotubes (F/N) structure. The PANI F/N is a 100‐nm thick PANI film embedded with PANI nanotubes. This well‐controlled method requires no surfactant or organic acid as well as relatively low concentration of reagents. Synthesis condition studies reveal that aniline oligomers with certain structures are responsible for guiding the growth of the nanotubes. Electrical characterization also indicates that the PANI F/N possesses similar field‐effect transistor characteristics to bare PANI film. With its 20% increased surface‐area‐to‐volume (S/V) ratio contributed by surface embedded nanotubes and the excellent p‐type semiconducting characteristic, PANI F/N shows clear superiority compared with bare PANI film. Such advantages guarantee the PANI F/N a promising future toward the development of ultra‐high sensitivity and low‐cost biosensors © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3973–3979

The effect of transition metal ions (M2 + = Mn2 +, Ni2 +, Co2 +, Cu2 +) on the chemical synthesis polyaniline as counter electrodes in dye-sensitized solar cells

The effect of transition metal ions (M2+=Mn2+, Ni2+, Co2+, Cu2+) on the chemical synthesis of polyaniline (PANI) used as a platinum-free counter electrode (CE) in dye-sensitized solar cells (DSSCs) was investigated. PANI was synthesized by co-polymerization of aniline in the presence of different transition metal ions by using potassium dichromate in acidic medium. It was found that the ion doping of PANI showed a certain catalytic activity for the regeneration of traditional iodide/triiodide (I−/I3−) redox couples. The power conversion efficiency (η) of PANI CEs doped with Mn2+, Ni2+, Co2+ (4.41%, 2.36% and 2.10%, respectively) were higher than 1.94%, the value measured for PANI CE without doping. Doping with Cu2+ decreased the power conversion efficiency of PANI CE (PANI-Cu2+η=1.41%). The electrical properties of the PANI, PANI-Ni2+, PANI-Co2+, PANI-Mn2+ and PANI-Cu2+ were studied by cyclic voltammetry (CV), impedance (EIS), and Tafel polarization curve. The experimental results confirmed that PANI was affected by the doping of different transition metal ions (M2+=Mn2+, Ni2+, Co2+, Cu2+). These results indicate a potential application of ion doped PANI as counter electrode in cost-effective DSSCs.

Chemical synthesis of polyaniline in the presence of poly(amidosulfonic acids) with different rigidity of the polymer chain

Conducting polyaniline (PANI) was chemically synthesized in the presence of water-soluble aromatic polyamides containing sulfonic groups: poly-(p,p’-(2,2′-disulfonic acid)-diphenylene-tere-phthalamide) (t-PASA, rigid backbone), poly-(p,p’-(2,2′-disulfonic acid)-diphenylene-iso-phthalamide) (i-PASA, semi-rigid backbone) and their copolymer (co-PASA) with the monomers ratio 1:1, as well as in the presence of flexible-backbone polyacids: poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and poly(styrene sulfonic acid) (PSSA). In these conditions the matrix polymerization of aniline results in the formation of water-soluble interpolymer complexes of PANI with the above cited polyacids. The character of spectral changes in the UV, visible and near IR (UV–Vis–NIR) range during the synthesis and the polymerization rates depend strictly on the structure of polyacid matrix. Higher flexibility of the polyacid backbone (PAMPSA, PSSA) contributes to higher relative absorption of localized polarons (750 nm), while in the spectrum of interpolymer complexes with rigid-chain polyacid (t-PASA) the absorption of delocalized polarons (1300–1500 nm) prevails. The complexes with semi-flexible i-PASA and co-PASA exhibit intermediate behavior. The results are interpreted in terms of differences in the inter-chain interactions in the interpolymer complexes of different structure. Fourier transform infrared (FTIR) spectroscopy data support the assumption of the incorporation of the polyacids in the PANI through an interaction between sulfonic groups of the polyacids and nitrogen atoms of PANI. Spectroelectrochemical and electrochemical (cyclic voltammetry) studies of the films cast from the obtained solutions showed that the formation of quinoid units at high oxidation level is retarded in the interpolymer complexes of PANI with rigid- and semi-rigid-chain polyacids. Atomic force microscopy (AFM) and direct current (DC)-conductivity data are also presented.

Synthesis and characterization of single‐wall‐carbon‐nanotube‐doped emeraldine salt and base polyaniline nanocomposites

AbstractNanocomposites of polyaniline (PANI) and single‐wall carbon nanotubes (SWNTs) were prepared and characterized via resonance Raman and electronic absorption spectroscopy (ultraviolet–visible/near‐infrared). The chemical synthesis of PANI was performed in the presence of SWNTs in concentrations ranging from 10 to 50 wt % (SWNT/PANI). The obtained materials were hydrophilic, homogeneous composite compounds. The chemical interaction between PANI (in the conducting emeraldine salt form and in the insulating emeraldine base form) and metallic and semiconducting nanotubes was investigated. The emeraldine salt form of the polymer was significantly stabilized in the composite in comparison with plain PANI. A selective electronic interaction process between PANI and metallic SWNTs was found. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 815–822, 2005

Hexachloroplatinate-Initiated Synthesis of Polyaniline/Platinum Composite

The chemical synthesis of polyaniline (PANI) is explored using hexachloroplatinate, PtCl62. These studies provide a simple method for the spontaneous oxidation of aniline by PtCl62- and simultaneous formation of gram quantities of PANI/Pt composite. The degree of Pt incorporation and subsequent encapsulation is based on a multistep reduction/oxidation process. The first step involves the reduction of PtCl62- to PtCl42- or Pt(0) and formation of the aniline radical cation in solution. The further reduction of PtCl42- to Pt(0) can also occur after aniline oligomers and polymer are formed in solution. The platinum colloids act as nucleation sites for the polymer forming the PANI/Pt composite, which precipitates from solution. Elemental analysis, XPS, and FTIR studies of the material indicate the properties of the polymer are consistent with the formation of a polymer salt containing metallic Pt. SEM images indicate that the Pt particles have maximum diameters on the order of 0.5−1 μm with some aggregation of...

Chemical Synthesis of a Polyaniline/Gold Composite Using Tetrachloroaurate

The chemical synthesis of polyaniline (PANI) is explored using tetrachloroaurate, AuCl4-. These studies provide a simple method for the oxidation of aniline by AuCl4- and simultaneous formation of bulk quantities of a PANI/Au composite. In situ UV/vis spectroscopy indicates that the rate of formation of gold colloids and intermediate (short-chain) PANI species is rapid in comparison to that of the long-chain PANI. Longer PANI chains are produced at a slower rate, at the expense of short-chain intermediate species. The gold particles act as nucleation sites for the oxidative formation of PANI, encapsulating the metal in the form of a polymer/metal composite. Results from the elemental analysis and the FTIR spectra of the composite material are consistent with PANI produced using only ammonium persulfate as the oxidant. In addition, XPS, optical microscopy, and TEM diffraction show that the gold particles are polycrystalline with relatively constant diameter (0.8−1 μm). Finally, the PANI/Au/HBF4 conductance does not change significantly with the introduction of Au particles, relative to that of PANI/HBF4 without Au particles. These studies provide a new method for growth of PANI/metal composites where the presence of the metal in the polymer does not adversely affect the electronic structure.

Chemical synthesis of polyaniline using sulphanilic acid as dopant agent into the reactional medium

Abstract The chemical synthesis of polyaniline (PAni) in a reactional medium containing sulphanilic acid (AS) as a dopant agent leads to a polymer with an electrical conductivity of 3 S cm−1. Thermogravimetrical analysis (TGA) showed that the doped polymer PAni-AS had a degradation temperature lower than the emeraldine-base polymer, due to the loss of the doping agent, water and low molecular weight oligomers. Scanning electronic microscopy (SEM) allowed to see that the polymer morphology is similar to other polymers described in the literature.

Electrochemical and chemical synthesis of polyaniline on the surface of vacuum deposited polyaniline films

Electrochemical and chemical synthesis of polyaniline (PAN) was performed in an aqueous acidic solution of aniline on the surface of vacuum deposited thin polyaniline films applied on an SnO 2 glass electrode. The composite films obtained have a high homogeneity and uniform thickness, essential for vacuum deposited layers. Spectroelectrochemical characteristics of the composite layers prepared by electrochemical synthesis are similar to those of electrodeposited PAN. Composite layers prepared by chemical synthesis have different Spectroelectrochemical characteristics, probably due to the presence of by-products of chemical synthesis. High selectivity of the synthesis was observed on the covered areas of partly sputtered substrates, evidently due to the autocatalytic character of PAN synthesis.