Electrosyntheses and characterization of poly(9-bromophenanthrene) in boron trifluoride diethyl etherate

A novel semi-conducting polymer poly(9-bromophenanthrene) (P9BP) was synthesized electrochemically by direct anodic oxidation of it is monomer 9-bromophenanthrene (9BP) in boron trifluoride diethyl etherate (BFEE). The oxidation onset potential of 9BP in this medium was measured to be only 1.33 V vs. saturated calomel electrode (SCE). P9BP films obtained from BFEE showed good electrochemical behavior and nice thermal stability with electrical conductivity of 0.03 S cm⁻¹. FTIR and ¹H NMR spectra together with theoretical quantum chemistry calculations indicated that the P9BP was mainly grown via the coupling of the monomer at C₃ and C₆ positions. Furthermore, P9BP exhibited strong electrochromic nature from opaque green to light yellow between the doped and dedoped states on ITO electrode in solid state. Fluorescence spectral studies indicated that P9BP was a blue light emitter.     

Electrosyntheses of freestanding poly (3-(4-fluorophenyl)thiophene) films in boron trifluoride diethyl etherate

High quality free-standing poly (3-(4-fluorophenyl)thiophene) (PFPT) films with conductivity of 10⁻¹ S/cm were electrosynthesized in boron trifluoride diethyl etherate (BFEE) by direct anodic oxidation of the monomer 3-(4-fluorophenyl)thiophene (FPT) on stainless steel sheet. As-formed flexible and shiny PFPT films can be cut into various shapes by a knife or a pair of scissors. The structure, thermal stability and morphology of PFPT films were studied by FT-infrared, UV-vis, Raman spectroscopy thermogravimetric analysis and scanning electron microscopy, respectively.     

Electrosyntheses of poly(2,3-benzofuran) films in boron trifluoride diethyl etherate containing poly(ethylene glycol) oligomers

Visible-light transparent high-quality substrate-supported poly(2,3-benzofuran) (PBF) film has been successfully electrosynthesized by direct anodic oxidation of 2,3-benzofuran on stainless steel sheet in boron trifluoride diethyl etherate (BFEE) containing 10% poly(ethylene glycol) (PEG) with molar mass of 400 (by volume). The oxidation potential of 2,3-benzofuran in this medium was measured to be only 1.0 V vs. SCE, which is lower than that determined in acetonitrile + 0.1 M Bu₄NBF₄ (1.2 V vs. SCE). The PBF films obtained in this media showed good electrochemical behaviors and good thermal stability with conductivity of 10⁻² S cm⁻¹, and the doping level of as-prepared PBF films was determined to be only 8.9%. The structure and morphology of the polymer were investigated by UV-vis, infrared spectroscopy and scanning electron microscopy (SEM), respectively. To the best of our knowledge, this is the first case for the syntheses of PBF films.     

Enzymatic synthesis and characterization of a water-soluble, conducting poly(o-toluidine)

An enzymatic method for the synthesis of a water-soluble, conducting poly(o-toluidine) (POT) in the presence of sulfonated polystyrene (SPS) is presented. The enzyme horseradish peroxidase was used to polymerize o-toluidine to form a water-soluble, conducting POT/SPS complex, which exhibits moderate electrical conductivity. The synthesis is simple and the conditions are mild. The polymerization may be carried out at room temperature in pH 4.3 buffered aqueous solution with stoichiometric amount of monomer, SPS, hydrogen peroxide and catalytic amount of enzyme. The UV-Vis absorption spectra of the products display a distinct absorption peak at 740 nm at pH 4.3 that indicates the formation of the conducting, emeraldine salt form of POT. The structure and electrochemical behavior of the polymer was investigated with FT-IR and cyclic voltammetry method.     

Electrosyntheses and characterization of a fluorescent conducting copolymer of benzanthrone and thiophene

<正>Poly(benzanthrone-co-thiophene),a new conducting copolymer,was successfully prepared by direct anodic oxidation of benzanthrone and thiophene(Th) in a binary solvent system containing boron trifluoride diethyl etherate (BFEE) and acetonitrile(ACN).The as-formed copolymer film electrodeposited with monomer feed ratio of benzanthrone/Th = 1:1 at the applied potential of 1.3 V versus Ag/AgCl exhibited the advantages of both polybenzanthrone and polythiophene,such as active electrochemical behavior,excellent thermal stability,relatively high electrical conductivity and mechanical properties.UV-Vis spectroscopy,~1H-NMR and SEM were used to characterize and investigate the structures and morphologies of the copolymers.Fluorescence spectroscopy studies revealed that the obtained copolymer films show strong emission at about 525 nm.Moreover,the emitting properties of the copolymers could be tuned by changing some parameters during the electropolymerization process,such as monomer feed ratio.     

Electrosynthesis and characterization of aminomethyl functionalized PEDOT with electrochromic property

We herein report the electrosynthesis of an aminomethyl functionalized poly(3,4-ethylenedioxythiophene)(PEDOT) derivative, poly(2'-aminomethyl-3,4-ethylenedioxythiophene)(PEDOT-Me NH2), in CH2Cl2-Bu4NPF6(0.1 mol·L-1) system containing 2% boron trifluoride diethyl etherate(BFEE). The electrochemical behavior, structure characterization, thermal properties and surface morphology of this novel polymer were systematically investigated by cyclic voltammetry(CV), Fourier-transform infrared spectroscopy(FTIR), thermogravimetry(TG) and scanning electron microscopy(SEM), respectively. Electrochemistry results demonstrated that PEDOT-Me NH2 film displayed good redox properties and high electrochemical stability. Besides, PEDOT-Me NH2 films exhibited the electrochromic nature with obvious color changing from purple in the reduced form to blue upon oxidation. By further investigation, kinetic studies revealed that PEDOT-Me NH2 film had decent contrast ratio(41.8%), favorable coloration efficiency(152.1 cm2·C-1), low switching voltages and moderate response time(2.4 s). Satisfactory results implied that the obtained PEDOT-Me NH2 film is a promising optoelectronic material and holds promise for electrochromic devices and display applications.     

Electroactivity, electrochemical stability and electrical conductivity of multilayered films containing poly(3,4-ethylendioxythiophene) and poly(N-methylpyrrole)

Multilayered systems of poly(3,4-ethylendioxythiophene) and poly(N-methylpyrrole) have been prepared using a layer-by-layer electrodeposition technique. The electrochemical and electrical properties of films formed by 3, 5, 7 and 9 layers have been characterized and compared with those of pure polymers and copolymers prepared from mixtures of 3,4-ethylendioxythiophene and N-methylpyrrole with various concentration ratios. Results indicate that the electroactivity and electrical stability of the multilayered systems are higher than those of both poly(3,4-ethylendioxythiophene) and copolymers. Furthermore, these electrochemical properties improve when the number of layers increases. On the other hand, the electrical conductivity of the multilayered systems is slightly lower than that of pure poly(3,4-ethylendioxythiophene), and significantly higher than those of poly(N-methylpyrrole) and copolymers.     

Synthesis and characterization of a new soluble conducting polymer and its electrochromic device

A mixture of isomers 2,5-di(4-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole, 2-(4-methyl-thiophen-2-yl)-5-(3-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole and 2,5-di(3-methyl-thiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (Me-SNS(NO₂)) were synthesized. Resulting monomers were polymerized chemically, producing soluble polymers in common organic solvents. The average molecular weight has been determined by gel permeation chromatography (GPC) as Mn=5.6×10³ for the chemically synthesized polymer. The monomers were also electrochemically polymerized in the presence of LiClO₄, NaClO₄ (1:1) as the supporting electrolyte in acetonitrile solvent. Resulting polymers were characterized via CV, FTIR, NMR, SEM and UV–Vis spectroscopy. Spectroelectrochemistry analysis of polymer revealed Π–Π^* transition below 300 nm, with an electronic band gap of 2.18 ev. Switching ability of the polymer was evaluated by kinetic study measuring percent transmittance (%T) at the maximum contrast point, indicating that poly(Me-SNS(NO₂)) is a suitable material for electrochromic devices.     

ELECTROCHEMICAL POLYMERIZATION OF 5-CYANOINDOLE IN MIXED ELECTROLYTES OF BORON TRIFLUORIDE DIETHYL ETHERATE AND DIETHYL ETHER

High quality poly（5-cyanoindole） （P5CI） films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate （BFEE） and diethyl ether （EE） （by volume 1：1） ＋ 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide （DMSO） while partly soluble in tetrahydrofuran （THF） or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.     

Electrosyntheses of high quality poly(5-methylindole) films in mixed electrolytes of boron trifluoride diethyl etherate and diethyl ether

High quality poly(5-methylindole) (P5MeI) films, especially with good fluorescence properties, were synthesized electrochemically by direct anodic oxidation of 5-methylindole in boron trifluoride diethyl etherate (BFEE) containing additional 50% diethyl ether (EE) (by volume). The oxidation potential onset of 5-methylindole in this medium was measured to be only 0.84 V vs. SCE, which was much lower than that determined in acetonitrile + 0.1 mol L⁻¹ TBATFB (1.08 V vs. SCE). P5MeI films obtained from this medium showed good electrochemical behavior and good thermal stability with conductivity of 10⁻² S cm⁻¹, indicating that BFEE was a better medium than acetonitrile for the electrosyntheses of P5MeI films. Dedoped P5MeI films were thoroughly soluble in strong polar solvent such as dimethyl sulfoxide (DMSO). ¹H NMR spectroscopy and FT infrared spectrum of dedoped P5MeI films strongly suggested that the monomers were linked via the positions 2 and 3. Fluorescent spectral studies indicated that P5MeI was a good violet-blue light emitter with the excitation and emission wavelength of 310 nm and 418 nm, respectively. To the best of our knowledge, this is the first case that 5-methyl group substituted polyindole films with good fluorescence properties can be electrodeposited.     

Electrosyntheses of free-standing poly(dibenzo-18-crown-6) films in boron trifluoride diethyl etherate on stainless steel electrode

High-quality free-standing poly(dibenzo-18-crown-6) (PDBC) films with a conductivity of 4.1 × 10⁻² S cm⁻¹ and good thermal stability were synthesized electrochemically on stainless steel electrode by direct anodic oxidation of dibenzo-18-crown-6 (DBC) in pure boron trifluoride diethyl etherate (BFEE). In this medium, the oxidation potential onset of DBC was measured to be only 0.98 V vs. SCE, which was much lower than that in acetonitrile + 0.1 mol L⁻¹ Bu₄NBF₄ (1.45 V vs. SCE). PDBC films obtained from this medium showed good redox activity and stability in BFEE. The structural characterization of PDBC was performed using UV-vis, FTIR spectroscopy. The results of quantum chemistry calculations of DBC monomer and FTIR spectroscopy of PDBC films indicated that the polymerization mainly occurred at C₍₄₎ and C₍₅₎ positions). Fluorescent spectral studies indicated that PDBC was a blue light emitter. To the best of our knowledge, this is the first report on the electrodeposition of free-standing PDBC films.     

Photophysical properties of PPP and PPV derivatives bearing polystyrene or polycaprolactone as side groups

This contribution reports on detailed photophysical investigations of poly(p-phenylene) PPP and poly(p-phenylene-vinylene) (PPV) derivatives laterally decorated with polystyrene (PPV-PSt) or poly(ε-caprolactone) (PPP-PCL, PPP-altPCL, PPV-PCL and PPV-PCL-Br). The polymers emit blue and exhibit very high relative and absolute photoluminescence quantum yield, Φ_f, in dilute solution, thin film (spin-coated and inkjet-printed) and bulk state. This is ascribed to the presence of the lateral macromolecules, which suppress the strong π-π interactions and consequently excimers formation. Lower Φ_f value was obtained for the bromine containing polymer and its corresponding model compound dibromodistyrylbenzene Br₂-DSB, which was ascribed to heavy atom effect enabling intersystem crossing from S₁ to T₁. However, studies at 77 K did not reveal phosphorescence, in contrast an enhancement of the fluorescence intensity with respect to room temperature measurement was observed.     

Novel conjugated polymer poly(benzobisoxazole-2,6-diylvinylene): synthesis and evidence of aggregate formation in methanesulfonic acid

A new conjugated polymer poly(benzobisoxazole-2,6-diylvinylene) (PBOV) has been synthesized as an analogue of poly(p-phenylene benzobisoxazole) (PBO). The comparison between PBOV and PBO has been carried out by Fourier transform infrared spectroscopy, thermogravimetric analysis, UV, and photoluminescence (PL) spectroscopy. The UV absorption peaks, PL excitation and emission wavelengths of PBOV have a significant red-shift due to the better electronic delocalization. Similar to PBO, it can be observed in the PL spectra of PBOV at various concentrations in methanesulfonic acid (MSA) that the intensity of emission was depressed and the highly structured emission spectra gradually changed to featureless, red-shifted, and broad spectra with increasing concentration. The change in emission spectra can be attributed to the existence of the interchain aggregates, although PBOV does not show highly ordered structure as PBO does.     

Electrosynthesis of highly conducting poly(1,5-dihydroxynaphthalene) in BF3·Et2O

Direct anodic oxidation of 1,5-dihydroxynaphthalene (DHN), an important derivative of naphthalene, led to the formation of high-quality semiconducting poly(1,5-dihydroxynaphthalene) (PDHN) on stainless steel sheets in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of DHN in this medium was measured to be only 0.78 V vs. SCE, which was lower than that determined in traditional acetonitrile containing 0.1 mol/L tetrabutylammonium tetrafluoroborate (0.98 V vs. SCE). As-formed PDHN films showed good redox activity and stability, together with interesting electrochromic property from brown (doped) to yellow-green (dedoped). Structural characterization, including FTIR, ¹H NMR, and quantum chemistry calculations, indicated that the polymerization of DHN probably occurred at C₄ and C₈ positions. Moreover, thermal analysis revealed that PDHN displayed better thermal stability than that synthesized by chemical method. The fluorescence spectral studies, together with the electrical tests, showed that PDHN was a good blue light-emitter (fluorescence quantum yield higher than 0.1) with an electrical conductivity of as high as 0.46 S/cm.     

Monodisperse and isolated microspheres of poly(N-methylaniline) prepared by dispersion polymerization

Monodisperse and isolated microspheres of poly(N-methylaniline) were successfully prepared through chemical polymerization of N-methylaniline by in adipic acid containing poly(vinylpyrrolidone) (PVP). Mean diameters of the microspheres with smooth surfaces changed from 320 to 100 nm by increasing the reaction temperature from 25 to 75 °C. The concentration of PVP did not affect much the size of microspheres, but the increased PVP concentration led to longer induction times for the onset of dispersion polymerization.     

Direct electrosynthesis and characterization of a new soluble polyfluorene derivative containing carboxyl group in boron trifluoride diethyl etherate

High-quality poly(fluorene-9-acetic acid) (PFAA), a new soluble polyfluorene derivative, was synthesized electrochemically by direct anodic oxidation of fluorene-9-acetic acid (FAA) in boron trifluoride diethyl etherate (BFEE) containing a certain amount of trifluoroacetic acid (TFA). This electrolyte enables facile anodic oxidation of FAA monomer at lower potential (1.05 V vs. SCE). PFAA films with conductivity of 0.53 S cm⁻¹ obtained from this medium showed better redox activity and thermal stability in relation to unsoluble poly(fluorene-9-carboxylic acid). Fluorescent spectral studies indicate that PFAA film with high fluorescence quantum yields and photochemical stability is a good blue-light emitter. The structure and morphology of the polymer were studied by UV–vis, FT-IR, ¹H NMR spectra and scanning electron microscopy, respectively.     

Porosity development in chars from thermal decomposition of poly(p-phenylene terephthalamide)

The main objective of this work was to investigate the development of porosity in solid residues from the thermal decomposition of the polymer, poly(p-phenylene terephthalamide) (PPTA). PPTA chars were prepared at different temperatures and characterized by X-ray diffraction and physical adsorption of CO₂ at 0 °C. The carbonization temperatures were selected on the basis of thermogravimetric analysis results. The effect of introducing an isothermal treatment at 500 °C on the characteristics of the resulting chars was also studied. It was found that this pre-treatment lowers the decomposition temperature of PPTA and yields a somewhat less ordered material than in the case of pyrolysis under a constant heating rate. The micropore volume increases with increasing heat treatment temperature for both series of samples. The mean micropore size decreases for the two series of chars until the 700-800 °C interval; above these temperatures, this evolution is reversed. The micropore volume of the samples submitted to the isothermal treatment is higher than when PPTA is treated under a constant heating rate. Likewise, the pore size distribution is more heterogeneous when the intermediate isothermal treatment at 500 °C is introduced during PPTA pyrolysis. Some differences between porosity development in chars from PPTA and other high thermal stability polymers were explained on the basis of different mechanistic features in polymer pyrolysis.     

Porosity development in chars from thermal degradation of poly(p-phenylene benzobisoxazole)

The main objective of this work was to investigate porosity development in carbonaceous materials formed by thermal degradation of the high thermal stability polymer, poly(p-phenylene benzobisoxazole) (PBO). Two varieties of PBO, as-spun (AS) and high-modulus (HM) were studied. Chars obtained at various polymer decomposition temperatures (selected on the basis of thermogravimetric and differential thermal analysis results) were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction and CO₂ adsorption at 273 K. The obtained adsorbents essentially contained narrow micropores, and maximum pore development took place at ca. 1000 K, when the polymer was not yet completely decomposed. At higher temperatures, there is a certain pore widening along with a displacement towards smaller pore sizes, and the pore volume significantly decreases.     

Electrochemical polymerization of 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole as a novel immobilization platform for microbial sensing

Two types of bacterial biosensor were constructed by immobilization of Gluconobacter oxydans and Pseudomonas fluorescens cells on graphite electrodes modified with the conducting polymer; poly(1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole) [SNS(NO₂)]. The measurement was based on the respiratory activity of cells estimated by the oxygen consumption at − 0.7 V due to the metabolic activity in the presence of substrate. As well as analytical characterization, the linear detection ranges, effects of electropolymerization time, pH and cell amount were examined by using glucose as the substrate. The linear relationships were observed in the range of 0.25–4.0 mM and 0.2–1.0 mM for G. oxydans and P. fluorescens based sensors, respectively.     

New confined p-phenylenevinylene (PPV)-type polymer analogue of poly(phenylene sulfide)

A new confined p-phenylenevinylene (PPV)-type polymer (PPVS) has been synthesized using Wittig condensation. The chemical structure of the polymer was well defined by ¹H NMR, ¹³C NMR, and FTIR spectroscopic analysis. PPVS contains oligomeric PPV units separated by sulfide bridges in the main chain; it is fully soluble in common organic solvents and has a number-average molecular weight of 3500 g mol⁻¹. Thermogravimetric analysis and differential scanning calorimetry indicate that PPVS is amorphous, stable up to 360 °C in air and displays a glass transition temperature of 98 °C. The optical properties of the polymer were investigated by UV-visible absorption and photoluminescence spectroscopies. The polymer film absorbs at 375 nm and emits at 517 nm with a narrow emission spectrum. From the cyclic voltammetry analysis, the electrochemical bandgap was estimated to be 2.78 eV. A single-layer diode device of the configuration indium-tin oxide/PPVS/aluminium has been fabricated and has a relatively low turn-on voltage of 3.4 V. An electroluminescent emission similar to photoluminescence is demonstrated in a multilayer device.