Electrochemical Copolymerization Of Aniline Research Articles

Electrodeposition of nanoporous conjugated copolymer on functionalized carbon cloth with extraordinary cycling stability for high-performance flexible supercapacitors

Conjugated polymers (CPs) have been widely used as pseudocapacitive materials in supercapacitors owing to their excellent conductivity and low processing costs. However, their low ionic diffusivity, sluggish charge transfer kinetics, and volume shrinkage/expansion during charging/discharging seriously reduce the capacity and cycle stability. Here, electrochemical copolymerization of aniline and 1,5-diaminoanthraquinone (DAA) was conducted on functionalized carbon cloth (FCC) to tune the structure and morphology of CPs for a better application in high-performance flexible supercapacitors. At an optimized feeding ratio, nanoporous conjugated copolymer coated FCC (FCC@PDA-AN-4) was obtained, possessing a high areal specific capacitance of 2847 mF cm−2 at 1 mA cm−2 with superior cycle life of 127.3% of its initial capacitance after 10,000 cycles.

Synthesis of Phosphorus-Containing Polyanilines by Electrochemical Copolymerization.

In this study, the phosphonation of a polyaniline (PANI) backbone was achieved in an acid medium by electrochemical methods using aminophenylphosphonic (APPA) monomers. This was done through the electrochemical copolymerization of aniline with either 2- or 4-aminophenylphosphonic acid. Stable, electroactive polymers were obtained after the oxidation of the monomers up to 1.35 V (reversible hydrogen electrode, RHE). X-ray photoelectron spectroscopy (XPS) results revealed that the position of the phosphonic group in the aromatic ring of the monomer affected the amount of phosphorus incorporated into the copolymer. In addition, the redox transitions of the copolymers were examined by in situ Fourier-transform infrared (FTIR) spectroscopy, and it was concluded that their electroactive structures were analogous to those of PANI. From the APPA monomers it was possible to synthesize, in a controlled manner, polymeric materials with significant amounts of phosphorus in their structure through copolymerization with PANI.

Electrochemical aptasensor based on conductive supramolecular polymer hydrogels for thrombin detection with high selectivity

Herein, we synthesized a kind of conductive supramolecular polymer hydrogel (CSPH) based on polyaniline (PANI) which can not only improve the conductivity but also promote antifouling performance of the aptasensor for the specific recruitment of thrombin (TB) from complex samples. With the electrochemical copolymerization of aniline (AN) and 3-aminophenylboronic acid (ABA) on glassy carbon electrode (GCE), the electrode was then inserted into the polyvinyl alcohol (PVA) solution to obtain robust CSPH through boric acid groups incorporated onto PANI to cause gelation of PVA solution, owing to the hydrophilicity of CSPH and nearly electrical neutrality, the modified electrode is antifouling without integration of other antifouling materials. A sandwich-type electrochemical aptasensor was constructed on the CSPH based electrode interfaces. Thrombin aptamer 1 (TBA1) were modified on the CSPH through amide bond, and thrombin aptamer 2 modified magnetic nanoparticles (MNP-TBA2) are used as signal amplification probes, the aptasensor has good sensitivity with a linear range from 1 pmol/L to 10 nmol/L and has a detection limit down to 0.64 pmol/L. The strategy of utilizing eletropolymerization of CSPH films to undergo highly selective thrombin recognition is, of course, readily extended to a broad range of targets in the real samples, and the recovery was ranging from 95.2% to 106.3% and RSDs varying from 2.3% to 4.5%.

Tuning the optical pH sensing properties of polyaniline-based layer by electrochemical copolymerization of aniline with o-phenylenediamine

The effect of copolymerization with o-phenylenediamine on polyaniline optical pH sensing properties is studied in this paper. The polyaniline and o-phenylenediamine based copolymers were formed electrochemically by potential cycling. Molecular structures of the deposited copolymer layers were investigated by Fourier-transform infrared spectroscopy. The pH sensing properties of resulting copolymer layers were studied by spectrophotometric titration as the function of o-phenylenediamine concentration in the polymerization solution. It was determined that pH at which the deposited polymer film exhibited the highest change in absorbance with respect to the change in solution acidity could be adjusted from pH 5.9 to pH 6.7 by the addition of the small amount of o-phenylenediamine to the polymerization solution. The potential applicability of the presented findings has been also discussed. The simplicity of here presented method could be found useful in the design of optical pH and gas sensing systems dedicated for various applications.

Corrosion protective poly(aniline-co-o-anisidine) coatings on mild steel

Syntheses of corrosion protective poly(aniline-co-o-anisidine) (PAOA) coatings were carried out on mild steel by the electrochemical copolymerization of aniline with o-anisidine under cyclic voltammetry conditions. An aqueous salicylate solution was used as the supporting electrolyte for the synthesis of PAOA coatings on mild steel. These coatings were characterized with cyclic voltammetry, ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and scanning electron microscopy. The FTIR and 1H-NMR spectroscopy studies reveal that during copolymerization of aniline and o-anisidine, there are more o-anisidine units than aniline units in PAOA copolymer. The corrosion protection offered by PAOA coatings to mild steel was investigated in aqueous 3% NaCl solutions using the potentiodynamic polarization technique. The results of the potentiodynamic polarization measurements showed that the PAOA coatings provided more effective corrosion protection to mild steel than the respective homopolymers. The corrosion rate was observed to be dependent on the feed ratio of o-anisidine used for synthesis of the copolymer coatings.

The electrochemical synthesis and properties of poly(aniline-co-diphenylamine and 5-aminosalicylic acid) with p-type doping and n-type doping

Poly(aniline-co-diphenylamine and 5-aminosalicylic acid) with p-type and n-type doping segments is first synthesized via electrochemical copolymerization of aniline, diphenylamine (DPA) and 5-aminosalicylic acid (5-ASA) in a solution of N, N-dimethylformamide (DMF) and sulfuric acid; a potential separation between two doping states is ≥ 1V, depending slightly on pH in a pH range of 4.0 to 13.3. For simplicity, the product of the electrochemical copolymerization, i.e., poly(aniline-co-diphenylamine and 5-aminosalicylic acid), is called copolymer. Evidence for both doping types comes from results of cyclic voltammetry of the copolymer in the wide pH range and wide sweeping potential region. The p-type doping state of the copolymer is not only related to aniline units in the copolymer chain, but also related to the potential region of the cathodic scan. The copolymer is a mixture of oligomers that are proven by mass spectral analysis. The measurements of electron spin resonance (ESR) demonstrate that free radicals are present in the copolymer. In particular, the copolymer shows evident photoelectric response under visible light illumination in aqueous media.

Poly(aniline-co-p-aminobenzoic acid): A Conducting Copolymer with Broadened Useful pH Range and Electrochemically Controllable Ion Exchange Behavior

A novel conducting polymer, poly(aniline-co-p-aminobenzoic acid) (PAABA), was successfully synthesized via electrochemical copolymerization of aniline and p-aminobenzoic acid (p-ABA) in 2 M H2SO4 solution. The results of FTIR and SEM revealed the differences between the obtained copolymer and its two corresponding homopolymers. Compared to polyaniline which has a rather limited useful pH range, PAABA presents excellent redox activity from pH < 1.0 to pH 10.0. The ion exchange properties of the copolymer were also investigated by using electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry, demonstrating a special anion exchange behavior different from polypyrrole. In other words, the spatial structure of anions instead of the radius of anions studied plays a key role in the anion exchange affinity sequence.

Electrochemical synthesis and characterization of poly(aniline-co-1-amino-9,10-anthraquinone), a nanosized conducting copolymer

The electrochemical copolymerization of aniline (ANI) with 1-amino-9,10-anthraquinone (1-AAQ) was carried out in 4 M sulfuric acid by potential cycling in the potential range of −0.1 V to 1.3 V vs. SCE. Copolymer films were grown from different feed ratios of ANI and 1-AAQ (0.2:0.8, 0.4:0.6, 0.5:0.5, 0.6:0.4, 0.8:0.2) on a glassy carbon electrode (GCE). Studies on the effect of scan rate on the conductivity of the copolymer film confirmed the formation of a stable conducting copolymer film. The FTIR spectrum recorded for the copolymer film provides concrete evidence of copolymer formation, since it indicates the presence of quinone units in the copolymer backbone. XRD data (particle size: 47 nm) and SEM (grain size: 100 nm) micrographs provide a clear picture of the nano-sized polymeric particles formed. It is envisaged that the newly reported copolymer could be a useful material for performing the catalytic reduction of oxygen in an acidic medium—a useful process for fuel cell applications.

Synthesis and Electronic Properties of Poly(aniline-co-2-amino-4-hydroxybenzenesulfonic acid)

Poly(aniline- co-2-amino-4-hydroxybenzenesulfonic acid) (PAAHB) was first synthesized via the electrochemical copolymerization of aniline and 2-amino-4-hydroxybenzenesulfonic acid (AHB) in the presence of an ionic liquid. The conductivity of PAAHB in the oxidized state is 0.45 S cm(-1). The conductivity and ESR spectra of PAAHB are slightly affected by water. The cyclic voltammograms of PAAHB reveal excellent redox activity from pH<1 to pH 11.0. This is attributed to the synergistic effect of the -SO3- and -OH functional groups in the copolymer chain and the ionic liquid incorporated into the PAAHB film. It is evident that the pH dependence of the redox activity and conductivity of PAAHB is much better than that of polyaniline. The proton NMR spectra of PAAHB and AHB demonstrate that the -SO3- group exists in the copolymer chain instead of the -SO3H group. Therefore, PAAHB can be used for the determination of dopamine in the presence of ascorbic acid as a result of the -SO3- group, which plays an important role in the selectivity.

Electrochemical synthesis of copolymer of aniline and o-aminophenol and its use to the electrocatalytic oxidation of ascorbic acid

Poly(aniline- co- o-aminophenol) (PAN–OAP) has been synthesized by electrochemical copolymerization of aniline (AN) and o-aminophenol (OAP) on glassy carbon electrode (GCE). FT-IR, UV–vis and electrochemical characterizations indicate the formation of the PAN–OAP and it has the structure of a head-to-tail coupling of AN and OAP units. When the concentration ratio of OAP–AN is more than 1:20, the voltammetric behaviors for the copolymerization of AN and OAP are similar, while the copolymerization rate decreases with increasing of OAP concentration in the solution. The PAN–OAP can maintain its electroactivity in neutral and even in alkaline media, although the electroactivity of the copolymers decrease with increasing of the concentration ratio of OAP–AN in solution. The PAN–OAP film coated GCE exhibits excellent electrocatalytic responses towards the electro-oxidation of ascorbic acid (AA) in phosphate buffer solution of pH 6.8. The anode peak potential of AA shifts from 0.53 V at bare GCE to 0.21 V at PAN–OAP/GCE with greatly enhanced current response. A linear calibration graph is obtained over the AA concentration range of 5 × 10 −4–1.65 × 10 −2 mol L −1 using cyclic voltammetry. Chronoamperometry has also been employed to investigate the electro-oxidation of AA. The PAN–OAP/GCE shows good stability and reproducibility.

Study on Electrochemical Copolymerization of Aniline and 3‐Methylthiophene in HMIMBF4 Ionic Liquid and Its Properties

AbstractElectrochemical polymerization of aniline and 3‐methylthiophene has been accomplished in 1‐methylimidazium tetrafluoroborate (HMIMBF4) ionic liquid. Homopolymer and copolymers of aniline and 3‐methylthiophene were obtained successfully. The copolymer was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The formation of copolymer has been confirmed by FT‐IR and UV spectra. The atomic force microscope (AFM) was used for microstructural analysis. Both the homopolymer and the copolymer had the catalytic activity for the hydroquinone.

Electrochemical synthesis of self-doped polyaniline and its use to the electrooxidation of ascorbic acid

Self-doped polyaniline (PAN) film on platinum electrode surface has been synthesized via electrochemical copolymerization of aniline with orthanilic acid (OAA). Fourier transform infrared, UV–Vis, and elemental analysis indicate the formation of the copolymer and that the copolymer has the structure of a head-to-tail coupling of aniline and OAA units. It was found that the internal doping of PAN with OAA can extend the electroactivity of PAN in neutral and even in alkaline media. The obtained self-doped PAN (PAN-OAA)-coated platinum electrode is shown to be a good surface for the electrooxidation of ascorbic acid (AA) in phosphate buffer solution of pH 7. The anode peak potential of AA shifts from 0.63 V at bare platinum electrode to 0.34 V at the PAN-OAA-modified platinum electrode with greatly enhanced current response. A linear calibration graph is obtained over the AA concentration range of 5–60 mM using cyclic voltammetry. Rotating disk electrode voltammetry and chronoamperometry have been employed to investigate the electrooxidation of AA. The PAN-OAA-modified platinum electrode shows good stability and reproducibility.

Studies on electrochemical copolymerization of aniline with o-phenylenediamine and degradation of the resultant copolymers via electrochemical quartz crystal microbalance and scanning electrochemical microscope

Electropolymerization of aniline in sulfuric acid solution in the presence of o-phenylenediamine ( oPD) of various concentrations was investigated via the electrochemical quartz crystal microbalance (EQCM) technique. It was found that the polymerization occurred more favorably at high aniline-to- oPD molar ratios ( F 1, 20 or above). The stabilities of the resultant copolymers against degradation were efficiently improved compared with that of polyaniline (PANI). The first-order kinetic constants for polymer degradation were estimated to be 2.07 × 10 −3 s −1 for polyaniline, and 3.91 × 10 −4 and 1.28 × 10 −4 s −1 for copolymers with F 1 values of 50 and 20, respectively. The degradation product, benzoquinone, was also detected at the tip electrode of a scanning electrochemical microscope (SECM).

Electrochemical copolymerization of aniline with m-aminophenol and novel electrical properties of the copolymer in the wide pH range

A copolymer, poly(aniline- co-m-aminophenol), has been synthesized using repeated potential cycling. The monomer concentration ratio, acid concentration and applied potential strongly affect the copolymerization rate and the properties of the copolymer. The optimum conditions for the copolymerization are that the scan potential range is controlled between −0.10 and 0.95 V (vs.SCE), and a solution consists of 0.34 M aniline, 0.012 M m-aminophenol and 2 M H 2SO 4. The IR spectra of the copolymers demonstrate that the m-aminophenol units are included in the copolymer chains. The cyclic voltammograms of the copolymers in 0.3 M Na 2SO 4 solution with various pH values were performed at the potential ranges from −0.20 to 0.80 V and at a scan rate of 60 mV s −1. The results indicate that the copolymer still hold 41.7% of the electrochemical activity when the copolymer electrode was transferred from a solution of pH 5.0 to a solution of pH 11.0 in the potential range of −0.20 to 0.80 V. An impedance plot of the copolymer in a solution with pH 12.0 and at 0.40 V is constructed of a semicircle and a Warburg line with a slope of 1. This means that the electrode reaction of the copolymer at pH 12.0 is also under mass transfer control. The conductivity of the copolymer prepared under the optimum conditions is 1.42 S cm −1, and slightly depends on the pH value. Thus, the pH dependence of the electrical properties of the copolymer is improved compared with poly(aniline- co-o-aminophenol), and is much better than that of the parent polyaniline.

In situ electrochemical and surface plasmon resonance (SPR) studies of aniline-carboxylated aniline copolymers

Self-doped conducting polyanilines (PAn) were fabricated by electrochemical copolymerization of aniline and carboxylated anilines in acidic aqueous solution using cyclic voltammetry. The comparative studies of carboxyl substituted and unsubstituted polyanilines show that only the copolymers from aniline (An) and 2-anthranilic acid (AA) with appropriate monomer fractions retain a high electroactivity and stability on electrodes in neutral aqueous solution. The polymerization process, the redox properties and the stability of the copolymers in comparison with those of polymers on gold electrodes were thoroughly investigated by in situ electrochemistry and surface plasmon resonance spectroscopy (SPR). The “self-inhibiting effect” and the “autocatalytic effect” were observed in the substituted and the unsubstituted polyanilines separately during the polymerization processes monitored by SPR. The combination of electrochemical and SPR techniques provides the direct information about the changes of dielectric properties and film thickness of the polymers in their redox processes. Comparing with those of PAn and copolymers, the dielectric constants of the substituted polyaniline play a minor role in the SPR reflectivity when it changes between different redox states. The comparable electroactivity of these copolymers obtained from aniline and its substituted analogues in acidic environments indicates the presence of a similar conjugated structure of the copolymer and the polyaniline, which is further confirmed by total internal reflection FTIR (TIR-IR).

Electrochemical copolymerization of aniline and ortho-aminobenzylamine. Studies on its conductivity and chemical derivatization

The electrochemical copolymerization of aniline and o-aminobenzylamine (ABA) leads to a polymer with aliphatic amino groups able to be derivatized. The synthesized material has a stoichiometry ABA:aniline ca. 1:1 when their ratio in the precursor solution range between 90:10 and 75:25. It presents similar conducting properties as polyaniline in acid medium. The conductance of the prepared polymer shows significant improvement compared to polyaniline in weak acidic to neutral media. The resulting product is able to be derivatized by mild reactions with molecules bearing a carboxylate or a carbonyl group. We show that approximately 20% of the added functional groups can be easily modified.

Raman spectroelectrochemical study of self-doped copolymers of aniline and selected aminonaphthalenesulfonates

Novel self-doped polyaniline-like copolymers have been prepared by electrochemical copolymerization of aniline with four aminonaphthalenesulfonates. All copolymer films prepared show their electrochemical redox activity even in pH-neutral solutions at a midpoint potential around 0.0 V versus Ag/AgCl. Raman spectroelectrochemical study of the copolymers prepared has been done with a red laser excitation (632.8 nm) within a broad electrochemical potential window of 0.0–1.0 V, and specific Raman features have been identified. Raman bands within the range of 1300–1400 cm −1 have been discussed regarding localized or delocalized polaronic ν s(C N +) vibrations. The influence of sulfonate group position in aminonaphthalenesulfonates on the parameters of polaronic bands has been demonstrated.

Polyaniline with Two Types of Functional Groups: Preparation and Characteristics

AbstractSummary: Polyaniline with two types of functional groups (sulfonated poly(aniline‐co‐o‐aminophenol), s‐copolymer) has been prepared by the electrochemical copolymerization of aniline and o‐aminophenol in sulfuric acid solution followed by sulfonation of the copolymer in the concentrated sulfuric acid. There are SO3H groups and OH groups in the s‐copolymer. The presence of SO3H groups on the polymer chain enables the s‐copolymer to possess intrinsic protonic doping ability. The OH group on the polymer chain can be oxidized and reduced reversibly. The shape of the cyclic voltammogram of the s‐copolymer is very similar to that of polyaniline in 0.2 M H2SO4 solution, in the potential range −0.20 to 0.80 V (vs. SCE). The results from cyclic voltammograms indicate only 22.8 and 31.6% decay of the electrochemical activity that was observed when the s‐copolymer electrode was transferred from the solution of pH 5.0 to the solutions of pH 10.0 and 11.0, respectively. Especially, there are still two pairs of redox peaks on the cyclic voltammogram of the s‐copolymer in 0.3 M Na2SO4 solution of pH 11.0 at the scan rate of 6 mV s−1. In this case, its usable potential range is 0.0–0.60 V. The s‐copolymer has a conductivity of 0.85 S cm−1, which is slightly dependent on pH when equilibrated with water. The spectra of FTIR, XPS, and ESR of the s‐copolymer are represented here.The cyclic voltammograms of (1) poly(aniline‐co‐o‐aminophenol) and (2) s‐copolymer in H2SO4 solution.magnified imageThe cyclic voltammograms of (1) poly(aniline‐co‐o‐aminophenol) and (2) s‐copolymer in H2SO4 solution.

Synthesis of aniline?thiophene copolymer on ?-PbO2 electrode in acetonitrile

Electrochemical copolymerization of aniline and thiophene was investigated on β-PbO2 electrode in acetonitrile. Optimum experimental conditions were determined forcopolymerization. Copolymer films synthesized on β-PbO2 electrode were analyzed bycyclic voltammetry, dry conductivity measurements, FT-IR spectroscopy, elemental analysisand thermal methods.

Electrochemical copolymerization of aniline and o-aminophenol

Poly(aniline-co- o-aminophenol) has been synthesized electrochemically in the solution consisting of 0.2 M aniline, 0.6 M H 2SO 4 and various concentrations of o-aminophenol. The copolymerization rate and the properties of the copolymer are strongly affected by the monomer concentration ratio. The copolymerization rate is about half of the electrochemical polymerization rate of aniline in the absence of o-aminophenol based on cyclic voltammetry. The cyclic voltammogram of the copolymer obtained at the optimum conditions is very similar to that of polyaniline in 0.2 M H 2SO 4 solution in the potential range −0.20 to 0.75 V (versus SCE), but a cathodic current plateau between 0.02 and 0.14 V on the cyclic voltammogram of the copolymer replaces a cathodic peak at 0.02 V on the cyclic voltammogram of polyaniline. The cyclic voltammograms of the copolymer in 0.3 M Na 2SO 4 solution of pH value from 5.0 to 9.6 were performed between −0.20 and 0.50 V at the scan rate of 60 mV/s. The results indicate that only a 29% decay of the electrochemical activity was observed when the copolymer was moved from pH 5.0 to 9.6. The electrochemical activity of poly(aniline-co- o-aminophenol) is about four times as high as that of polyaniline in 0.3 M Na 2SO 4 solution of pH 5.0. A surprising result shows that two pairs of the redox peaks still appear on the cyclic voltammogram of the copolymer in the solution of pH 9.6 at the scan rate of 6 mV/s. In this case, its usable potential range is −0.20 to 0.62 V. The copolymer has a good stability and a high reversibility in the above solutions, and has a conductivity of 1.40 S/cm. The FT-IR spectrum and XPS spectrum of the copolymer are represented here.