Electrochemical preparation and characterization of poly(1-amino-9,10-anthraquinone) films

Poly(1-amino-9,10-anthraquinone), PAAQ, films were prepared by electrochemical oxidation of the monomer, AAQ, in acetonitrile using LiClO₄ as supporting electrolyte. The influence of scan repetition, scan rate and monomer concentration on the formation of polymer film was studied. The electrochemical behavior of the formed polymer films was investigated in both non-aqueous and aqueous media. The prepared films were found to be more stable in organic solvents than in aqueous solutions. The investigated organic solvents are methanol, ethanol, acetone, carbon tetrachloride, benzene, and chloroform. The polymer film shows electrochemical response in both non-aqueous and aqueous media. In non-aqueous solutions it has a wide potential range of electroactivity (from −1.5 to +1.3 V). In aqueous media the polymer film shows electrochemical response in the potential range between −0.3 and +1.3 V only. The presence of quinone units suggests potential applications in diverse areas such as electrocatalytic processes and lithium ion batteries.     

Optimization of the electropolymerization of 1-amino-9,10-anthraquinone conducting films from aqueous media

The optimum conditions for the electrochemical preparation of poly(1-amino-9,10-anthraquinone), PAAQ, films in environmentally safe aqueous solutions were investigated. The conducting polymer films were prepared by electrochemical oxidation of 1-amino-9,10-anthraquinone, AAQ, in sulfuric acid solutions in the potential range from 0.0 to +1.3 V. The influence of scan repetition, scan rate, and monomer concentration on the formation process and the properties of the polymer film were studied. The electrochemical response of the formed polymer film was investigated in both aqueous and non-aqueous media. The polymer films were found to be stable in aqueous acidic media. In non-aqueous solutions, like acetonitrile, dimethyl sulfoxide and dioxin, the polymer films showed remarkable degradation. The best electrochemical response of the PAAQ films was found to be in the potential range between +0.3 and +0.9 V. The presence of quinone units in the polymer film chain suggests promising applications of these conducting polymers in lightweight (rechargeable) batteries, electrochromic display devices, and biosensor and corrosion protection.     

Photophysical processes and interactions between poly(ethylene terephthalate) and 1-amino-2-(2-methoxyethoxy)-4-hydroxy-9,10-anthraquinone

The effect of 1-amino-2-(2-methoxyethoxy)-4-hydroxy-9,10-anthraquinone (C. I. Disperse Red 59) on the phototendering of poly(ethylene terephthalate) (PET) was assessed. The photophysical processes occurring in the polymer, the dye, and the dyed polymer were determined. The energy and nature of the dye and polymer electronic excited states were assigned on the basis of absorption and luminescence properties. Irradiation failed to produce dye-sensitized phototendering of PET; however, the titanium dioxide delusterant in commercial PET did function as a sensitizer in the presence of moist air. The phototendering of blank-dyed PET yarn was found to obey (pseudo-) zero-order kinetics k = 1.69 × 10^?19 per cent breaking strength loss/quantum absorbed/cm². The dye exhibited fluorescence from a lowest, ～51.5 kcal/mole, singlet charge-transfer (C-T) excited state but did not phosphoresce. The PET possessed a complex fluorescence spectrum attributed to similar ¹(n,π^*)₁ excited states, ～78.1 kcal/mole, while its phosphorescence derives from a proposed ³(π,π^*) state, ～69.8 kcal/mole, populated by intersystem crossing from a ¹(π,π^*) state, ～92.3 kcal/mole. The dyed polymer exhibited a PET-sensitized delayed fluorescence from the dyestuff involving triplet–singlet transfer by a dipole–dipole (Coulumbic) long-range resonance excitation mechanism. The transfer process was characterized by an experimentally determined critical transfer distance, R₀, of approximately 40 Å.     

Electrochemical preparation and characterization of conducting copolymer/silica composite

A composite based on organic copolymer and inorganic oxide, polyaniline/poly o‐toluidine/silica (PANI/POT/SiO₂), has been synthesized successfully by a simple electrochemical method. The composite film was found to be deposited on a Pt substrate by sweeping the potential between ?0.2 and +1.0 V versus a saturated calomel electrode with a scan rate of 100 mV/s. The polymeric composite film thus obtained was characterized by scanning electron microscopy, infrared spectroscopy, conductance measurement, and cyclic voltammetry techniques. Incorporation of silica in the copolymer results a clear difference in surface morphology compared with the bulk homo‐ and copolymers. Further evidence of silica in the composite was achieved by infrared spectral analysis. Indeed, a chemical analysis of the composite matrix showed a content of as high as 25% SiO₂ in the composite thus prepared. Based on the results of cyclic voltammetric analysis, the composite electrode as prepared was found to show good electrochemical stability even at high positive potentials. It also exhibited excellent electroactivity even after incorporation of silica in the matrix. The electroactive composite film was thus examined as electrode modifier to study the redox behavior of ferrous/ferric (Fe²⁺/Fe³⁺) and hydroquinone/benzoquinone (H₂Q/Q) couples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrochemical synthesis and characterization of poly(m-toluidine)

Poly(m-toluidine) was prepared by electrochemical polymerization of the corresponding monomer on gold and tin oxide electrodes, in acid medium. The polymer was characterized by elemental analysis, cyclic voltammetry,I-t curves and scanning electron microscopy. The utility of poly(m-toluidine) as an anion-exchange film is demonstrated on the basis of the electrostatic incorporation of anionic redox species into the poly(m-toluidine) film.     

Electrochemical synthesis and characterization of poly(pyrrole‐co‐ε‐caprolactone) conducting copolymer

The direct electrochemical copolymerization of pyrrole (Py) and ε‐caprolactone at various monomer ratios was carried out by potentiostatic methods in nitromethane. Characterizations of the novel copolymer were based on scanning electron microscopy, differential scanning calorimetry, thermal gravimetrical analysis, cyclic voltammetry, electrochemical impedance spectroscopy, Fourier transform infrared spectra, and elemental analysis studies. The results showed that the electrochemical oxidation of Py and ε‐caprolactone comonomers generated true copolymers rather than blends of the two homopolymers. The electrical conductivity of the copolymers increased with the amount of polypyrrole in the copolymer between the value of 8.2 S/cm and 0.6 S/cm. A probable mechanism of copolymerization was proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Electrochemical synthesis and characterization of poly(9-benzylfluorene)

In this study, we report the electrochemical polymerization of 9-benzylfluorene (9-BF) in acetonitrile solution. The characterization of the resulting poly(9-BF) film obtained on the working electrode has been performed by using attenuated total reflectance infrared spectroscopy. Besides electrochemical properties, the optical and photoluminescent properties of film were also investigated in detail by means of UV–Vis spectroscopy and fluorescence spectroscopy. Fluorescent spectral studies indicate that polymer film in solid state emits blue-green light at around 470/520 nm under irradiation of UV light. In addition, scanning tunneling microscopy was used to investigate the morphology of poly(9-BF) film. The morphological results also reveal that the surface of single crystalline gold electrode is completely covered with the polymer film.     

Chemical synthesis and characterization of soluble conducting poly(2-aminothiazole)

Poly(2-aminothiazole), (P-2AT), was synthesized by chemical polymerization method using 2-aminothiazole as the monomer. Structural characterizations were carried out by Fourier transform infrared, nuclear magnetic resonance, UV-vis spectroscopy, elemental analysis and scanning electron microscopy techniques. Thermal characterizations were carried out by thermogravimetric analysis and differential scanning calorimetry techniques. The number average molecular weight, M_n, of the polymer was determined by gel permeation chromatography. The effects of monomer and initiator concentration and polymerization time on the polymer yield were also studied. The solubility of the P-2AT was tested in common organic solvents as well as in acidic and basic solutions. P-2AT was soluble in DMSO, THF and DMF and its conductivity value measured 3 × 10^?6 S/cm.     

Electropolymerization and characterization of polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol)

Applications of conducting polymers to biosensors have recently aroused much interest. This is because these molecular electronic materials offer control of different parameters such as polymer layer thickness, electrical properties and bio-reagent loading, diversity, ease of fabrication and potentially low cost, etc. Polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol) preparations are performed with electrochemical (CV) method at room temperature, in a standard three-electrode cell. Homopolymer and the copolymers of aniline and 2-anilinoethanol films were deposited from 1?M acidic aqueous media containing 0.2?M aniline, 2-anilinoethanol by voltammetric sweep between ?0.1 and 1 V Ag/AgCl, at 20?mV/s^?1. The sweep was stopped after 30 cycles at ?0.1?V Ag/AgCl and the working electrode was covered by homopolymer and copolymer of aniline and 2-anilinoethanol. Characterizations of the products were carried out by cyclic voltammograms, UV?Cvisible, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance (EIS) was employed to examine the water absorption of the synthesized polymers to be used in biosensor application. Electrochemical properties of polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol) were studied and it is shown that with increased (2-anilinoethanol) content in the copolymer, its electroactivity, conductivity and resistance are reduced, though the processability and adhesion properties improve. The hydrophilicity of polymer film obtained has increased with increasing (2-anilinoethanol) content which leads to salt moving to the surface of steel.     

Electrochemical synthesis and characterization of conducting copolymers of biphenyl with pyrrole

Copolymer films of biphenyl and pyrrole were synthesized by electrochemical polymerization. The influence of the applied potential used for the electropolymerization on the structure, morphology, electrical conductivity, and stability of the films was examined. From the analysis of the current–time curves, it was found that the growth of the copolymer films starts immediately. The films were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, X-ray diffraction analysis, and scanning electron microscopy–energy-dispersive X-ray analysis, and their electrical conductivity (σ), energy gap (E_g), and electrochemical stability were also determined. Based on the results, the copolymers were classified into three groups. The first includes the (PP-PPy)_0.80 copolymer synthesized at the lowest potential E_ox (0.80 V), having the highest ratio R (R = 0.35) of quinoid to benzenoid rings (calculated from FTIR), the highest value of σ (σ = 0.9 S/cm), the lowest E_g (E_g = 1.20 eV), and has compact morphology. The second group concerns the copolymers synthesized at higher potential (0.82 up to 0.86 V), having lower R (∼ 0.20), lower σ (below 0.4 S/cm), higher E_g (∼ 1.35 eV), and they are less compact with many pores. The third group includes the copolymers synthesized at even higher applied potential (0.88 and 0.90 V), having even lower R values (∼ 0.10), significantly lower σ (∼ 10⁻³ S/cm), even higher E_g (∼ 1.70 eV), and they are very porous. The applied potential during electropolymerization strongly affects the properties of the synthesized copolymers. Because of the combination of high conductivity, low energy gap, and partial solubility with significant electrochemical stability, these new copolymers are attractive candidates for many applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical synthesis and characterization of a novel thiazole-based copolymer and its application in biosensor

A novel copolymer based on 2-aminothiazole (AT) and 2-amino-4-thiazoleacetic acid (ATA) is electrochemically synthesized and then characterized using UV–visible absorption spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and electrochemical techniques. The results confirmed that the obtained polymer was a copolymer rather than a blend or a composite of the respective homopolymers and could improve the electrochemical response of both positively and negatively charged analytes. Therefore, the copolythiazole film was applied to determine ascorbic acid (AA), dopamine (DA) and uric acid (UA). It is found that the peak separating degrees and peak currents of AA, DA and UA at copolythiazole modified electrode were much better than those at bare GCE. Under the optimum conditions, the linear calibration curves were obtained in the range of 10–2000 μM for AA, 1–150 μM for DA, 1–180 μM for UA. The detection limits of AA, DA and UA were 2, 0.04 and 0.4 μM, respectively (S/N = 3). The practical application of the modified electrode was demonstrated by the determination of UA in urine sample.     

Electrochemical synthesis and characterization of poly(pyrrole-co-o-toluidine)

The electrochemical polymerization of o-toluidine has been investigated in oxalic acid solution. It was shown that the oxidation of monomer could be achieved but this process does not yield a stable, homogenous polymer film on either platinum or mild steel electrodes. Therefore the copolymerization between pyrrole and o-toluidine has been studied as an alternative method for obtaining good quality coating (low permeability and water mobility, high stability), which could also be easily synthesized on steel. For this aim, various monomer feed ratio solutions of pyrrole:o-toluidine 9:1, 8:2 and 7:3 have been examined, in aqueous oxalic acid solution. By using cyclic voltammetry technique, copolymer films were realized on platinum and steel, successfully. The temperature of synthesis solution was found to have a vital role on polymerization and film growth, as much as the monomer feed ratio. The synthesis of homogenous copolymer film could only be achieved under ≤25 °C conditions with using the 9:1 ratio, while the 8:2 ratios could only produce stable films below 5 °C. As the amount of o-toludine increased the required temperature value decreased further, 7:3 ratio could only give a stable copolymer film below 2 °C. The characterization of deposited copolymer coating has been realized by using SEM micrographs, UV–vis and FT-IR spectroscopy techniques and cyclic voltammetry. The protective behaviour of these coatings was also investigated against mild steel corrosion in 3.5% NaCl solution, by means of electrochemical impedance spectroscopy (EIS) and anodic polarization curves. It was found that the monomer feed 8:2 ratio gave the most effective coating against the corrosion of mild steel.     

Electrochemical synthesis and characterization of poly (o-amino benzyl alcohol) and poly (o-amino benzyl alcohol-co-o-anisidine)

In this study; poly (o-amino benzyl alcohol) and poly (o-amino benzyl alcohol-co-o-anisidine) copolymer films were electrochemically synthesized by cyclic voltammetry technique on the platinum electrode. The synthesis of copolymer films was achieved in various monomers feed ratio (o-amino benzyl alcohol: o-anisidine; 8:2, 1:1, 2:8) of o-amino benzyl alcohol and o-anisidine. Different solution types were tested in aqueous and non-aqueous media, especially during the synthesis process, as the electrolyte medium. As a result of the experiments, it was determined that sulfuric acid solution was the most suitable solution for both homopolymer and copolymer film growth. Homopolymer and copolymer samples were characterized by FT-IR, cyclic voltammetry (CV), SEM, digital images and TGA/DTA techniques. The CV, SEM and digital images results indicated that the solution which has high ratio of monomer is more effective in copolymer film synthesis mechanism. TGA results showed that the 1:1 copolymer film had higher thermal stability than the films at other monomer ratios. Also, electrochemical studies exhibited that the copolymer film in 1:1 ratio is partially more electrochemically stable than other copolymer films.     

Synthesis and characterization of poly(1-methyl-1-silabutane), poly(1-phenyl-1-silabutane) and poly(1-silabutane)

Summary Anionic ring opening polymerization of 1-methyl-1-silacyclobutane, 1-phenyl-1-silacyclobutane and 1-silacyclobutane co-catalyzed by n-butyllithium and hexamethylphosphoramide (HMPA) in THF at-78°C yields poly(1-methyl-1-silabutane), poly(1-phenyl-1-silabutane) and poly(1-silabutane) respectively. These saturated carbosilane polymers possess reactive Si-H bonds. They have been characterized by ¹H, ¹³C and ²⁹Si NMR as well as FT-IR and UV spectroscopy. Their molecular weight distributions have been determined by gel permeation chromatography (GPC), thermal stabilities by thermogravimetric analysis (TGA) and glass transition temperatures (T_g) by differential scanning calorimetry (DSC).     

3-甲基-1-对氯苯氧基-9,10-蒽醌的合成及光致变色性研究

报道了3-甲基-1-对氯苯氧基-9,10-蒽醌的合成、表征及其光致变色性,并通过核磁共振谱、质谱、红外光谱和紫外-可见光谱确定了结构.其紫外光谱图在389,312 nm处有2个等吸光点,有特征吸收单峰出现在482 nm处,其峰型有向双峰变化的趋势.由于苯氧基有吸电子取代基氯,导致其光致变色效果一般,但从紫外光谱图来看,其光致变色性还是比较明显.     

Linear, soluble poly(bismethylene hydroquinone), a ladder polymer: synthesis and characterization

A route to prepare a soluble linear ladder of poly(bismethylene hydroquinone) was developed. 2,3,5,6-Tetramethylol hydroquinone was reacted with hydroquinone in sulpholane with acid catalysis. Gel formation was prevented by removing the water generated during the condensation, and by preventing oxidation of the polymer during reaction. Polymers with intrinsic viscosities as high as 5.0 were obtained; viscosity depended on the mole ratio of the starting materials and the reaction conditions. Polymer structure was characterized by Fourier transform infra-red spectroscopy, nuclear magnetic resonance spectroscopy, polarizing microscopy and X-ray diffraction.     

Electrochemical synthesis and characterization of novel electrochromic poly (3,4-ethylenedioxythiophene-co-Diclofenac) with surfactants

Copolymers prepared from 3,4-ethylenedioxythiophene (EDOT) and Diclofenac (DCF) through cyclic voltammetric method exhibited electroactive and electrochromic behaviours. Addition of DCF produced bathochromic shift of the EDOT main absorption band from 253.4 to 269.7 nm in the UV-vis spectra. The cyclic voltammetric studies were carried out with different feed concentration of DCF and in the presence of two different surfactants, SDS and CTAB on glassy carbon electrode surface. Effect of scan rate on the three types of electroactive copolymer films was studied. The three different copolymers showed good adherence on the glassy carbon electrode surface in aqueous 0.1 M KCl medium. Spectroelectrochemical analysis of copolymer film was carried out on Indium-Tin-Oxide (ITO) plate and it showed multicolor electrochromic behaviour when the applied potential was changed. The color of the copolymer was changed from neutral yellow to brown and to violet in 0.1 M KCl medium. Among the three different copolymers, the copolymer prepared in presence of CTAB resulted in high contrast colors. The electrochromic parameters such as coloration efficiency, optical contrast, response time and stability were also evaluated. The surface morphology of the copolymer films was characterized by SEM analysis.     

Electrochemical polymerization and characterization of a functional dicarbazole conducting polymer

The electropolymerization of the unique dicarbazole monomer, 2,6-bis-carbazole-9-yl-hexanoic acid pentafluorophenyl ester, is reported. This chiral monomer possesses two carbazole units and a chiral grafting center, activated ester for covalent amine-coupling. Contrary to monocarbazole monomers unable of internal cross-linking, its specifically designed dicarbazole skeleton allowed us to obtain highly reticulated polydicarbazole films functionalized for probe coupling. Full analysis of its electrochemical polymerization revealed different oxidation potentials for the two structurally different carbazole units. The electrochemical activity of the polydicarbazole-coated electrode has been characterized in different redox electrolytes. Contacted by a model protein (BSA), this film has been easily passivated at the Rubpy₃(PF₆) electrochemical window.     

Electrochemical synthesis and characterization of poly(m-phenylenediamine) films on copper for corrosion protection

Poly(m-phenylenediamine) (PMPD) films were electrosynthesized on copper by using cyclic voltammetry in near-neutral aqueous sodium oxalate medium. Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy, scanning electron microscopy and atomic force microscopy were utilized to characterize the obtained PMPD films. Corrosion performances of uncoated and PMPD coated copper electrodes were investigated in 0.1 M H₂SO₄ by open circuit potential–time (E_ocp–t) curves, anodic polarization and electrochemical impedance spectroscopy techniques. Corrosion test results demonstrate that the PMPD coating appears to enhance protection of copper for considerable immersion periods. The percent protection efficiency value (E%) was found to be 80% even after 168 h immersion time in corrosive test solution.