Electrochemical polymerization of p‐terphenyl in mixed electrolyte of boron trifluoride diethyl etherate and CH2Cl2

High quality poly(p‐phenylene) (PPP) film with conductivity of 0.015 S cm^?1 was synthesized electrochemically by direct anodic oxidation of p‐terphenyl (PP) oligomers in boron trifluoride diethyl etherate (BFEE) containing 37.5% CH₂Cl₂ (v/v). The oxidation onset potential of PP in this medium was measured to be only 1.23 V vs. saturated calomel electrode (SCE), which was lower than that determined in CH₂Cl₂ + 0.1 mol L^?1 Bu₄NBF₄ (1.87 V vs. SCE). As‐formed PPP films showed good electrochemical behavior, good electrochromic property and good thermal stability. The structures and morphology of doped and dedoped PPP were investigated by UV‐vis, FTIR, and Scanning electron micrographs. The infrared spectroscopic measurements for the estimation of chain lengths revealed that PPP was composed of about 10 phenyl rings. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Expanding the chemistry of single‐ion conducting poly(ionic liquid)s with polyhedral boron anions

The synthesis of a new family of single‐ion conducting random copolymers bearing polyhedral boron anions is reported. For this purpose two novel ionic monomers, namely [B₁₂H₁₁(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂]^2?[(C₄H₉)₄N⁺]₂ and [8‐(OCH₂CH₂)₂OC(?O)C(CH₃)?CH₂‐3,3′‐Co(1,2‐C₂B₉H₁₀)(1′,2′‐C₂B₉H₁₁)]^?K⁺, having methacrylate function, diethylene glycol bridge and closo‐dodecaborate or cobalt bis(1,2‐dicarbollide) anions were designed. Such monomers differ from previously reported ones by (i) chemically attached highly delocalized boron anions, by (ii) valency of the anion (divalent anion and monovalent one) and by (iii) the presence of oxyethylene flexible spacer between the methacrylate group and bonded anion. Their free radical copolymerization with poly(ethylene glycol) methyl ether methacrylate and subsequent ion exchange provided lithium‐ion conducting polyelectrolytes showing low glass transition temperature (?53 to ?49 °C), ionic conductivity up to 9.1 × 10^?7 S cm^?1, lithium transference number up to 0.61 (70 °C) and electrochemical stability up to 4.1 V versus Li⁺/Li (70 °C). The incorporation of propylene carbonate (20–40 wt%) into the copolymers resulted in the enhancement of their ionic conductivity by one order of magnitude and significantly increased their electrochemical stability up to 4.7 V versus Li⁺/Li (70 °C). © 2019 Society of Chemical Industry     

Synthesis,Characterization and Properties of <Emphasis Type="Italic">N</Emphasis>-Alkyl-<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-di(2-hydroxyethyl) Amine Oxides

N‐Dodecyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C₁₂DHEAO) and N‐stearyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C₁₈DHEAO) were synthesized with N‐alkyl‐diethanolamine and hydrogen peroxide. Their chemical structures were confirmed using ¹H‐NMR spectra, mass spectral fragmentation and FTIR spectroscopic analysis. It was found that C₁₂DHEAO and C₁₈DHEAO reduced the surface tension of water to a minimum value of approximately 28.75 mN m^?1 at concentration of 2.48 × 10^?3 mol L^?1 and 32.45 mN m^?1 at concentration of 5.21 × 10^?5 mol L^?1, respectively. The minimum interfacial tension (IFT_min) and the dynamic interfacial tension (DIT) of oil–water system were measured. When C₁₈DHEAO concentration was in the range of 0.1–0.5%, the IFT_min between liquid paraffin and C₁₈DHEAO solutions all reached the ultra‐low interfacial tension. Furthermore, their foam properties were investigated by Ross‐Miles method, and the height of foam of C₁₂DHEAO was 183 mm. It was also found that they showed strong emulsifying power.     

Synthesis and characterization of electrically conducting copolymers based on benzene and biphenyl

Poly(p‐phenylene) (H‐PPP), which is one of the firstly investigated conducting polymer, has the disadvantage of difficult processability because it is infusible and insoluble. The use of biphenyl instead of benzene leads to ortho‐, meta‐, para‐polyphenylenes (H‐PP) which are more soluble and easier to be processed, however their electrical conductivity is lower. Copolymers of polyphenylenes (C₁ and C₂) and corresponding homopolymers (H‐PPP and H‐PP) were produced by the oxidative cationic polymerization of benzene and/or biphenyl. The soluble (‐S) and the insoluble (‐I) in chlorobenzene polyphenylenes were separated (H‐PP‐I, H‐PP‐S, C₁‐I, C₁‐S, C₂‐I, and C₂‐S) and they were doped with a solution of FeCl₃. All polyphenylenes were studied by FTIR, XRD, TGA, and their electrical conductivity with constant current was determined. Pronounced differences between the copolymers and the homopolymers were observed, indicating the different structure of the former. The values of the electrical conductivity of doped insoluble copolymers (10^?4 and 10^?5 S/cm) are between that of H‐PPP (10^?3 S/cm) and H‐PP‐I (10^?6 S/cm). The values of the electrical conductivity of doped soluble copolymers (10^?5 S/cm) are considerably higher than that of H‐PP‐S (10^?9 S/cm). The new electrically conductive polyphenylenes that were produced differ significantly from the corresponding homopolymers and combine good electrical conductivity and solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrodeposition of High-quality Polycarbazole Films in Composite Electrolytes of Boron Trifluoride Diethyl Etherate and Ethyl Ether

High-quality polycarbazole (PCZ) films were synthesized electrochemically by direct oxidation of carbazole in boron trifluoride diethyl etherate (BFEE) containing vol. 20% ethyl ether (EE). The oxidation potential of carbazole in this medium was measured to be only 0.90 V vs. SCE, which was lower than that determined in acetonitrile containing 0.1 mol l⁻¹ Bu₄NBF₄ (1.35 V vs. SCE). PCZ films obtained from this medium showed better electrochemical behavior, better thermal stability with conductivity of 7.5 × 10⁻³ S cm⁻¹ being one order of magnitude higher than those reported previously, indicating that BFEE/EE was a better medium than acetonitrile for the electrosyntheses of PCZ films. As-formed PCZ films can be partly dissolved in acetone, acetonitrile and tetrahydrofuran. Spectral analysis provided evidence for the existence of the conjugated structure of the PCZ chain. Fluorescent spectra indicate that electrosynthesized PCZ is an ideal blue light emitter.     

Electrochemical polymerization of 2‐phenylindole and characterization of its polymer

High‐quality poly(2‐phenylindole) (PPI) films were synthesized electrochemically by direct anodic oxidation of 2‐phenylindole (PI) in boron trifluoride diethyl etherate (BFEE). The onset oxidation potential of PI in this medium was measured to be only 0.83 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile (ACN) containing 0.1 mol L^–1 tetrabutylammonium tetrafluoroborate (1.05 V vs. SCE). PPI films obtained from BFEE showed good electrochemical behavior and thermal stability with an electrical conductivity of 10^–2 S cm^–1. Structural studies showed that the polymerization of PI mainly occurred at the 3,6‐positions. As‐formed PPI films could be partly dissolved in dimethyl sulfoxide. Fluorescence spectral studies indicated that PPI was a blue‐green light emitter. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on Micellar Behavior of PEO‐PBO or PEO‐PBO‐PEO Copolymers,or Surface Active Amphiphilic Ionic Liquids in Aqueous Media and Exploration of the Micellar Solutions for Solubilization of Dexamethasone and its Delayed Release

The aggregation behavior of a di‐ and tri‐block copolymers of type PEO‐PBO, PEO‐PBO‐PEO, surface‐active ionic liquid (SAIL) of type 4‐dodecyl‐4‐methylmorpholinium chloride [C₁₂mmor][Cl], and 1‐dodecyl‐1‐methylpyrrolidinium chloride [C₁₂mpyrr][Cl]) in water as well as in 10 mM of a poorly water soluble dexamethasone (dex) aqueous solution was studied by determining the critical micelle concentrations using drug solubilization, surface tension, and isothermal titration calorimetry (ITC) methods. ITC measurements were also made on solutions prepared by mixing the micellar aqueous solutions of copolymers and simple aqueous solutions of SAIL across the mole fractions at three different temperatures (298.15, 308.15, and 318.15 K). The thermodynamic parameters, namely Gibbs free energy (ΔG_m), enthalpy (ΔH_m), and entropy (ΔS_m), of micellization were calculated, and it was observed that the negative ΔG_m and positive ΔS_m for the mixture solutions increase with the increase in mole fraction of SAIL. Otherwise, the micellization is reported to be a spontaneous and highly entropy‐driven process. The dex‐solubilized micellar solutions were mixed with agar to obtain standing gels. The gel samples were dry‐cast into thin films, and the release of dex from films by simple dilution was monitored by UV measurements. The drug release data was fitted to several mechanistic models, and it was inferred that the release mechanism for dex from thin films is non‐Fickian for mixtures and Fickian in copolymer or SAIL micellar aqueous solutions. The transport of dex is diffusion‐controlled with diffusivities of 5.8–12 × 10^?11 m² s^?1 for copolymer micelles, 5–11 × 10^?11 m² s^?1 for micelles of SAIL, and 3–14 × 10^?11 m² s^?1 for the mixed micelles of copolymer and SAIL in aqueous media.     

Characterization of Biosurfactant Produced by a Novel Strain of Pseudomonas aeruginosa,Isolate ADMT1

Several biosurfactant‐producing bacterial strains were isolated from petroleum‐contaminated soil. The isolate ADMT1, identified as a new strain of Pseudomonas aeruginosa, was selected for further studies on the basis of oil displacement test and emulsification index (E24). The optimal parameters for production, determined by employing Box–Behnken design, were temperature 36.5 °C and pH 7. The environmental isolate ADMT1 produced significant amount of biosurfactant (1.7 g L^?1 in 72 h) in minimal salt medium (MSM) using dextrose as the sole carbon source. The E24 value and critical micelle concentration (CMC) of the biosurfactant was 100% and 150 mg L^?1, respectively. At CMC, the surface tension of water was reduced to 28.4 mN m^?1. The biosurfactant exhibited hemolytic activity and antibacterial activity against 8 reference strains of pathogenic bacteria, including 2 methicillin‐resistant Staphylococcus aureus strains (MRSA ATCC 562 and MRSA ATCC 43300), with minimum inhibitory concentration (MIC) of 0.4 and 0.2 mg mL^?1, respectively. The structure of biosurfactant was characterized by FTIR, ¹H, and ¹³C NMR spectroscopy. 7 di‐rhamnolipid (RL) congeners were identified in the biosurfactant by ultraperformance liquid chromatography–mass spectrometry analysis. The major congeners, which constituted 67% of the RL mixture, included Rha‐Rha‐C₁₀‐C₁₀, Rha‐Rha‐C₁₂‐C₁₀, and Rha‐Rha‐C_12:1‐C₁₀. The minor congeners were Rha‐Rha‐C₁₀‐C₈, Rha‐Rha‐C_10:1‐C₁₀, Rha‐Rha‐C₁₀‐C_14:1, and Rha‐Rha‐C₁₀‐C₁₄. The congener Rha‐Rha‐C₁₀‐C₁₄ is being reported for the first time from any species of Pseudomonas. The high surface activity and E24 value make the ADMT1‐RL a potential candidate for its use in detergents, environmental bioremediation, and as an emulsifier in the food industry.     

Electrochemical preparation of poly(N‐acetylaniline)/poly‐(4‐styrenesulfonic acid‐co‐maleic acid) composite film towards ascorbic acid sensing

Poly(N‐acetylaniline)/poly(4‐styrenesulfonic acid‐co‐maleic acid) (PNAANI/PSSMA) composite film was prepared by cyclic voltammetry (CV), and was characterized by FTIR and X‐ray photoelectron spectrum (XPS). The electroactivity of the composite film was high in neutral and basic solutions, and it had been used for amperometric determination of ascorbic acid (AA). Compared with pure PNAANI film, the catalytic activity of the composite film was much better. AA was detected amperometrically in sodium citrate buffer at a potential of 0.3 V (versus SCE). The response current was proportional to the concentration of ascorbic acid in the range of 4.7 × 10^?6 to 5.0 × 10^?5M and 5.0 × 10^?5 to 2.5 × 10^?3M, respectively, with the detection limit of 1.9 × 10^?6 mol L^?1 at a signal to noise ratio 3. In addition, the stability and reusability of the composite film were performed well, and it was satisfying to be used for determination of AA in real fruit juice samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrosyntheses and characterization of poly(5‐bromoindole) in boron trifluoride diethyl etherate

Poly(5‐bromoindole) (PBrI) films were synthesized electrochemically by direct oxidation of 5‐bromoindole in pure boron trifluoride diethyl etherate. The oxidation potential of 5‐bromoindole in this medium was measured to be only 0.97 V vs. saturated calomel electrode, which was lower than that determined in acetonitrile + 0.1 mol L^?1 Bu₄NBF₄ (1.08 V). PBrI films obtained from this medium showed good electrochemical behavior and good thermal stability. Structural studies showed that the polymerization of 5‐bromoindole ring occurred at 2,3 position. As‐formed PBrI films were thoroughly soluble in strong polar solvent dimethylsulfoxide and partly soluble in tetrahydrofuran. Fluorescent spectral studies indicated that PBrI was a good blue‐light emitter. The excitation and emission spectra of PBrI showed a significant shift to longer wavelength compared with that of the monomer, consistent with the greater extent of electron delocalization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 539–547, 2006     

Electrosynthesis of conducting polymer films from the azo dye methoxy red

Anodic polymerization of the azo dye methoxy red (4-methoxybenzene azo-1,3-diaminobenzene) on platinum electrodes in 1 M HCl in 50% v/v ethanol/water was found to yield thin and stable polymeric films. The films were electroactive in acidic solutions and the activity diminished as the acidity decreased. The pair of symmetrical redox peaks at a formal redox potential, (E )_pH=0 = 0.61 V vs SCE, with a Nernstian slope dE/dpH = 0.06 V, is attributed to a 1:1 proton + electron elimination (on oxidation)/addition (on reduction) at the amino/imino linkages which connect the aromatic nuclei. Chronocoulometric plots indicated that the transport of the solvated protons, and probably Cl^– ions, through the film is the rate-determining step of the above redox processes. The rate of electron transfer reactions of the redox couple [Fe(CN)₆]^3–/4– on poly-methoxy red-covered platinum electrodes decreased by a factor of more than two orders of magnitude, compared to the bare electrodes.     

Electrosyntheses of high quality free-standing poly(9-fluorenone) films in boron trifluoride diethyl etherate

High quality free-standing poly(9-fluorenone) (PFO) films were synthesized electrochemically by direct anodic oxidation of 9-fluorenone (FO) in pure boron trifluoride diethyl etherate (BFEE). The oxidation potential of FO in this medium was measured to be only 1.48 V versus SCE, which was greatly lower than that determined in CH₂Cl₂ + 0.1 mol l⁻¹ Bu₄NBF₄ (2.21 V versus SCE). PFO films obtained from BFEE showed good electrochemical behavior, good thermal stability with electrical conductivity of 7.8 × 10⁻³ S cm⁻¹, indicating that BFEE was a better medium than CH₂Cl₂ for the electrosyntheses of PFO films. Structural studies showed that the polymerization of FO ring occurred at 2,7-position. As-formed PFO films can be partly dissolved in acetone and tetrahydrofuran (THF). Fluorescent spectral studies indicate that PFO is a good blue light emitter. To the best of our knowledge, this is the first report on the electrosyntheses of free-standing PFO films.     

The grafting reaction of epoxycyclohexyl polyhedral oligomeric silsesquioxanes with carboxylic methoxypolyethylene glycols and the properties of composite solid polymer electrolytes with the graftomer

A novel organic–inorganic hybrid of epoxycyclohexyl polyhedral oligomeric silsesquioxane (e‐POSS)–grafted carboxylic methoxypolyethylene glycols (mPEG‐COOH), that is, a POSS‐mPEG graftomer, was synthesized. The grafting reaction of e‐POSS and mPEG‐COOH was characterized by Fourier transform infrared (FTIR) and ¹H‐NMR spectroscopy. Then the graftomer was used to develop new composite solid polymer electrolyte (SPE) films with a carboxylated nitrile rubber–epoxidized natural rubber (XNBR‐ENR) self‐crosslinked blend system as a dual‐phase polymer matrix. The self‐crosslinked reaction of the XNBR‐ENR matrix was investigated using ATR‐FTIR. The morphology of the SPE films and the distribution of lithium salt were investigated using field emission scanning electron microscopy and X‐ray diffraction, and the result illustrated that the addition of POSS‐mPEG could promote and accelerate the dissociation of LiClO₄. The best effect within the range of this study was achieved when 25 phr POSS‐mPEG was involved. The differential scanning calorimetry analysis proved that the glass‐transition temperature of the composite SPE films was reduced with the increase of POSS‐mPEG. The ionic conductivity of the composite SPE films was investigated by electrochemical impedance spectroscopy. The highest ionic conductivity in this study of 2.57 × 10^?5 S cm^?1 was obtained with 25 phr POSS‐mPEG loading. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44460.     

Surface Chemical Properties and Micellization of Disodium Hexadecyl Diphenyl Ether Disulfonate in Aqueous Solution

The surface tension of disodium hexadecyl diphenyl ether disulfonate (C₁₆‐MADS) was measured at different NaCl concentrations (0.00–0.50 mol L^?1) and temperatures (298.0–318.0 K) using the drop‐volume method. The results show that, with increasing temperature, the critical micelle concentration (CMC) of C₁₆‐MADS increases slightly, but the maximum surface adsorption capacity (Γ_max) at the air–water interface decreases. When the concentration of NaCl was increased from 0.00 to 0.50 mol L^?1, the CMC of C₁₆‐MADS decreased from 1.45 × 10^?4 to 4.10 × 10^?5 mol L^?1, but the surface tension at the CMC (γ_cmc) was not affected. When the concentration of NaCl was increased at 298.0 and 303.0 K, the Γ_max of C₁₆‐MADS increased. When the temperature was increased from 308.0 to 318.0 K, the surface excess concentration (Γ_max) of C₁₆‐MADS abnormally decreased from 2.26 to 1.41 μmol m^?2 with increasing NaCl concentration. The micellization free energy () decreased from ?63.98 to ?76.20 kJ mol^?1 with increase of temperature and NaCl concentration. The micellar aggregation number (N_m) of disodium hexadecyl diphenyl ether disulfonate (C₁₆‐MADS) was determined using the molecule fluorescence probe method with pyrene as probe and benzophenone as quencher. The results show that an appropriate N_m could be measured only at surfactant concentration above the CMC. The N_m increased with an increase in C₁₆‐MADS concentration, but the micropolarity in the micelle nucleus decreased. The temperature had little effect on N_m. Compared with typical single hydrophilic headgroup surfactants, aggregates of C₁₆‐MADS exhibit different properties.     

Synthesis and characterization of polyaniline/NiO nanocomposite

Spherical nickel oxide (NiO) nanoparticles were prepared by using nickel chloride as precursor in the ethylene glycol as solvent and urea as precipitant. The X‐ray diffraction study showed that NiO has single‐phase cubic structure with average crystallite size of 35 nm. The prepared NiO nanoparticles were incorporated into polyaniline (PANI) matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline: NiO (12 : 1, 6 : 1, and 3 : 1) at 5°C using (NH₄)₂S₂O₈ as oxidant in aqueous solution of sodium dodecylbenzene sulfonic acid, as surfactant and dopant under N₂ atmosphere. The synthesized composites have been characterized by means of X‐ray diffraction (XRD), thermogravimetric analysis, Fourier transform infrared (FTIR), scanning electron microscopy, TEM, and vibrating sample magnetometer for its structural, thermal, morphological, and magnetic investigation. The XRD and FTIR studies show that the NiO particles are in the composite. The room temperature conductivities of the synthesized PANI, PANI/NiO (12 : 1), (6 : 1), and (3 : 1) composites were found to be 3.26 × 10^?4, 1.88 × 10^?4, 1.5 × 10^?4, and 4.61 × 10^?4 S/cm, respectively. The coercivity (H_c) and remnant magnetization (M_r) of NiO, PANI/NiO NCs (12 : 1), (6 : 1), and (3 : 1) at 5 K was found to be 8.22 × 10^?2, 6.31 × 10^?2, 6.42 × 10^?2, 6.27 × 10^?2 T, and 6.64 × 10^?3, 1.83 × 10^?4, 3.07 × 10^?4, and 3.98 × 10^?4 emu/g, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Direct low‐potential electropolymerization of 9,10‐dihydrophenanthrene in boron trifluoride diethyl etherate

High‐quality poly(9,10‐dihydrophenanthrene) (PPh) with good fluorescence properties was synthesized electrochemically by the direct anodic oxidation of 9,10‐dihydrophenanthrene in boron trifluoride diethyl etherate (BFEE). PPh films obtained from BFEE‐based electrolytes showed good electrochemical behavior and good thermal stability with an electrical conductivity of 2.2 × 10^?3 S/cm; this indicated that BFEE was a better medium for the electrosyntheses of PPh films. Dedoped PPh films were soluble in CH₂Cl₂, dimethylformamide, and dimethyl sulfoxide. The structure and morphology of the polymer were also characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, ¹H‐NMR spectroscopy, and scanning electron microscopy, respectively, which indicated the polymerization mainly occurred at the C₍₂₎ and C₍₇₎ positions. Fluorescent spectral studies indicated that PPh was a good blue‐light emitter. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of Polar Organic Solvents on Self‐Aggregation of Some Cationic Monomeric and Dimeric Surfactants

Surface and micellization behavior of some cationic monomeric surfactants, viz., cetyldiethylethanolammonium bromide (CDEEAB), cetyldimethylethanolammonium bromide (CDMEAB), tetradecyldiethylethanolammonium bromide (TDEEAB) and dimeric surfactants, i.e., alkanediyl‐α, ω‐bis(dimethylhexadecylammonium bromide) (C₁₆‐s‐C₁₆, 2Br^? where s = 4, 12), butanediyl‐1,4‐bis(dimethyldodecylammonium bromide (C₁₂‐4‐C₁₂, 2Br^?) and 2‐butanol‐1,4‐bis(dimethyldodecylammonium bromide) (C₁₂‐4(OH)‐C₁₂, 2Br^?), was studied in water‐organic solvents [10 and 20 % v/v ethylene glycol (EG) and diethylene glycol (DEG)] by conductivity, surface tension and steady‐state fluorescence methods at 300 K. The main focus of the present work is on the study of the effect of organic solvents on the critical micelle concentration (CMC), Gibbs free energy of micellization (ΔG°_m), Gibbs free energy of transfer (ΔG°_trans), Gibbs adsorption energy (ΔG°_ads) and some interfacial parameters such as the surface excess concentration (Γ_max), minimum area per surfactant molecule (A_min) and surface pressure (π_CMC). The aggregation number (N_agg) and Stern‐Volmer quenching constant (K_SV) were also determined by the steady‐state fluorescence method. It was observed that N_agg decreased with increasing volume percent of organic solvent. The results exhibited an increase in CMC in water‐organic solvents as compared to the respective surfactants in pure water. The negative values of ΔG°_m and ΔG°_ads indicate a spontaneous micellization process. The thermodynamics of micellization revealed that the micellization‐reducing efficiency of glycols increases with the concentration and the number of ethereal oxygens in the glycol.     

Electrochemical method for quantitative determination of trace amounts of disperse dye in wastewater

The electrochemical behaviour of Disperse Red 13 dye at a glassy carbon electrode was investigated in both organic and aqueous organic mixtures. Best results were obtained in N,N‐dimethylformamide/Britton–Robinson buffer (1:1, v/v), which displays a well‐defined peak at ‐0.40 V (vs Ag/AgCl) owing to reduction of the protonated nitro group. This method can be successfully applied to the electroanalytical determination of Disperse Red 13 in a very simple and inexpensive way. All the differential pulse voltammetry parameters were optimised by using a glassy carbon electrode modified with poly(glutamic acid) films. The targeted analytical method presented a linear response from Disperse Red 13 concentrations between 2.5 × 10^?7 and 3 × 10^?6 mol l^?1 (r = 0.997), with a detection limit of 1.5 × 10^?8 mol l^?1 and recoveries of 89.7–95.10% in water samples. Disperse Red 13 was successfully determined in textile industry wastewater by means of the proposed method after pre‐extraction in a solid‐phase extraction cartridge.     

Synthesis of pentavalent imidovanadium complexes and their catalyses for the polymerization of ethylene and propylene

Imidovanadium complexes with cyclopentadienyl (Cp) ligands—(Cp)V(?NC₆H₄Me‐4)Cl₂ (1), (Cp)V(?N^tBu)Cl₂ (2), and (^tBuCp)V(?N^tBu)Cl₂ (3; ^tBuCp = tert‐butylcyclopentadienyl)—were synthesized through the reaction of imidovanadium trichloride with (trimethylsilyl)cyclopentadiene derivatives. The molecular structure of 3 was determined by X‐ray crystallography. The monocyclopentadienyl complex 1 exhibited moderate activity in combination with methylaluminoxane [MAO; 10.3 kg of polyethylene (mol of V)^?1 h^?1 atm^?1], whereas similar complexes with bulky ^tBu groups, 2 and 3, were less active. (2‐Methyl‐8‐quinolinolato)imidovanadium complexes, V(?NR)(O ?N)Cl₂ (R = C₆H₃ⁱPr₂‐2,6 (4) or n‐hexyl (5), O ?N = 2‐methyl‐8‐quinolinolato), were obtained from the reaction of imidovanadium trichloride with 2‐methyl‐8‐quinolinol. Upon activation with modified MAO, complex 4 showed moderate activities for the polymerization of ethylene at room temperature. The complex 5/MAO system also exhibited moderate activity at 0°C. The polyethylenes obtained by these complexes had considerably high melting points, which indicated the formation of linear polyethylene. Moreover, the 5/dried MAO system showed propylene polymerization activities and produced polymers with considerably high molecular weights and narrow molecular weight distributions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1008–1015, 2005     

Ionic conductivity of hybrid films based on polyacrylonitrile and their battery application

The alternate current (AC) and direct current (DC) ionic conductivity of hybrid films composed of polyacrylonitrile (PAN), lithium perchlorate (LiClO₄), and a plasticizer was studied. Three kinds of the plasticizer [ethylene carbonate (EC), propylene carbonate (PC), N,N-dimethylformamide (DMF)] were used. Suitability of these hybrid films for lithium battery was investigated. The AC conductivity, which represents bulk ionic conductivity, was dependent on the component and the composition of the hybrid films, ranging from 10^?4?10^?8 Scm^?1. The AC conductivity was mainly determined by the molar ratio of [plasticizer]/[LiClO₄] in the hybrid films and increased with the increase in this ratio. The effect of the plasticizer on the enhancement in the AC conductivity was in the following order. DMF>EC>PC. The hybrid films with both electrodes of lithium showed the stable DC conductivity of about 1/10 of the AC conductivity, except for the hybrid films containing DMF. The hybrid films were found to be effective as a lithium ionic conductor. The galvanic cell. Li/sample/MnO₂, at the discharge current density of 90 μA/cm² showed the stable electromotive force of about 3 V for 70 h.