电化学合成含交替苯/噻吩结构的电致变色聚合物

利用Kumada偶联合成了2,5-二苯基噻吩（DPT）、1,4-二噻吩基苯（DTP）及1,4-二（3-甲基-2-噻吩基）苯（DMTP）,并电聚合得到相应的聚合物PDPT、PDTP和PDMTP。PDPT的电化学稳定性较差,而PDTP和PDMTP在0～1.2 V间具有良好的电活性。此外,PDTP和PDMTP分别具有青-橙和红-绿-蓝的电致变色现象,可用于电致变色器件。     

Capacitive properties of promising energy storage material based on thiophene containing perylenediimide polymer

In this study, electropolymerization of pre-synthesized N,N′-di-[3-[2-(3-thienyl)ethyl] phenyl] perylene-3,4,9,10-bis(dicarboximide) (ThPDITh) was performed on Au button electrode and the properties of the resultant polymer P(ThPDITh) were investigated by electrochemical techniques. Effect of the polymerization charge on the redox behaviors of the polymer film was investigated by cyclic voltammetry (CV) and the polymer film was further characterized by electrochemical impedance spectroscopy (EIS) measurements. Corresponding electrical equivalent circuit was applied to the experimental data to explain the electrochemical phenomenon on the interface of the Au/P(ThPDITh). In order to obtain information on the energy storage properties of P(ThPDITh) as a pseudo-capacitive electrode material, important cell characteristics, such as redox process in anodic and cathodic potential ranges, stability of galvanostatic charge–discharge (GCD) curves, coulombic efficiency, capacitance, energy and power density values were determined. Capacitance values, obtained through different measurements (CV, EIS and GCD) are all in good agreement with each other. All the results suggested that P(ThPDITh) is capable of undergoing multiple reversible redox processes, and a good candidate for improving the capacitance and energy density of electrode material while still offering high power capability.     

Itaconic acid grafting on LDPE blended in molten state

Grafting of itaconic acid on low density polyethylene in the molten state has been investigated. Static and dynamic mixers assembled on the Brabender plastograph have been used as a blender of reagents and as a chemical reactor. Shear rates were 50 and 100 s⁻¹. Dicumyl peroxide; 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane; 2,2-di-(tert-butyl-peroxy)-5,5,6-trimethylbicyclo-[2,2,1]-heptane; 2,2-di(3-methyl-1-butyne-3-peroxy)-5,5,6-trimethylbicyclo[2,2,1]heptane; 2,5-dimethyl-2-hydroxy-5-tert-butylperoxy-3-hexyne were used as peroxide initiators of grafting. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1493–1502, 1997     

Electrochemical and theoretical studies of thienyl-substituted amino triazoles on corrosion inhibition of copper in 0.5 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript>

2,5-Bis(2-thienyl)-4-amino-1,2,4-triazole (2-TAT) and 2,5-bis(3-thienyl)-4-amino-1,2,4-triazole (3-TAT) have been studied as inhibitors for the corrosion of copper in 0.5 M H₂SO₄ using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The inhibition efficiency of the triazole compounds increases with increasing concentration, and the effect of 3-TAT is better than that of 2-TAT with the same concentration. Potentiodynamic polarization measurements indicate the triazole compounds act as mixed type inhibitors in 0.5 M H₂SO₄. The adsorption of the triazole compounds is found to obey the Langmuir adsorption isotherm. High significant correlations for the triazole compounds are obtained between inhibition efficiency and quantum chemical parameters (R = 0.975) using the quantitative structure–activity relationship (QSAR) method.     

Synthesis of conjugated polymers with broad absorption bands and photovoltaic properties as bulk heterojuction solar cells

Two new broad absorbing alternating copolymers, poly[1-(2,6-diisopropylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P1) and poly[1-(p-octylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P2), were prepared via Suzuki polycondensation with high yields. The two polymers were found to show characteristic absorption in the visible region of the solar spectrum. Interestingly the absorption of PTPTTBT-P1 was found to cover the visible region from 350 to 650 nm with the broad and flat absorption maximum from 440 to 510 nm in film and the absorption of PTPTTBT-P2 was found to cover the visible region from 350 to 950 nm with the relatively distinct absorption maxima at 425 and 522 nm and very weak absorption maximum at 832 nm in film. The electrochemical band gaps of the polymers were calculated to be 1.88 eV and 1.87 eV, respectively, while the optical band gaps of the polymers were calculated to be 1.94 eV and 1.87 eV, respectively. The photovoltaic properties of polymers were investigated with bulk heterojunction (BHJ) solar cells fabricated in ITO/PEDOT:PSS/polymer:PC₇₀BM(1:5 wt%)/TiOx/Al configurations. The maximum power conversion efficiency (PCE) of the solar cell composed of PTPTTBT-P1:PC₇₀BM as an active layer was 1.57% with current density (J_sc) of 8.17 mA/cm², open circuit voltage (V_oc) of 0.52 V and fill factor (FF) of 36%.     

Chemical and Electrochemical Polymerization of Thiophene Derivatives

Abstract

The synthesis and some physical properties of polymers containing the thiophene ring are described. The polymerization of 3-phenylthiophene (1), 2-phenvi-thiophene (2). 2,5-diphenylthiophene (3), 2-(2-thienyl) pyridine (4) and 3,6-bis(2-thienyl)pyridazine (5) under electrochemical and chemical conditions are reported. The monomers were prepared by the nickel or palladium catalyzed cross-coupling reactions and were electrochemically polymerized using galvanostatic conditions (platinum electrodes) or chemically polymerized by oxidation with iron trichloride. The effect of monomer concentration, electrolyte and solvent were studied. From the examined polymers only poly(3-phenylthiophene) showed significant properties, considering morphology and conductivity. The other polymers gave mainly powder or porous films with low conductivity. The thermogravimetry analysis of poly (3-phenylthiophene) showed a wide temperature range of thermal stability, only over 450°C considerable weight loss was observed. Scanning electron microscopy (SEM) of samples obtained under different conditions demonstrated the dependence of the morphology upon monomer structures, nature of the dopant and synthetic route employed.     

Two-photon absorption dyes with thiophene as π electron bridge: Synthesis, photophysical properties and optical data storage

Four novel dyes are prepared by thiophene as π bridge between carbazole central core and other terminal groups by Suzuki and Heck coupling reactions. These dyes are fully characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. Linear absorption, single- and two-photon excited fluorescence in various solvents are experimentally investigated. The calculated two-photon absorption cross sections of 9-Hexyl-3,6-di((5-phenyl)-2-thienyl)carbazole (1), 9-Hexyl-3,6-di((5-thienyl)-2-thienyl)carbazole (2), 9-Hexyl-3,6-di((5-p-vinylpyridyl)-2-thienyl)-carbazole (3) and 9-Hexyl-3,6-di-((5-o-vinylpyridyl)-2-thienyl)carbazole (4) for the lowest excited state are 537.84, 550.76, 1292.95 and 1340.40 × 10⁻⁵⁰ cm⁴ s photon⁻¹, respectively. Calculated and experimental data have shown that thiophene as π electron bridge improves the two-photon absorption cross sections greatly. Two-photon optical data recording experiments have been carried out at 820 nm laser radiation.     

In situ FTIR spectroelectrochemistry of poly[2-(3-thienyl)ethyl acetate] and its hydrolyzed derivatives

Poly[2-(3-thienyl)ethyl acetate] (PTEtAc) was chemically synthesized and transformed to partially hydrolyzed PTEtAc (PTEtAcOH) and poly[2-(3-thienyl)ethanol] (PTEtOH). The influence of the acetoxy and hydroxyl terminal functionalities in the side groups on the electrochemical properties of these polyalkylthiophenes was studied by cyclic voltammetry and in situ FTIR spectroelectrochemistry. The cyclic voltammograms point to a chemically reversible behaviour of the p-doping process for PTEtAc and PTEtAcOH, while for PTEtOH the redox activity of the polymer film is lost during consecutive potential scans.The attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to investigate the p-doping of the three different type of thiophene polymer films. In situ FTIR spectra taken at different electrode potentials in a cyclovoltammetric scan display the doping induced changes of the polymer pattern. Important differences in the behaviour of the polymers were observed and interpreted in terms of different film structures.     

A new processable donor–acceptor polymer displaying neutral state yellow electrochromism

We report here the synthesis of a new solution processable neutral state yellow polymeric electrochromic material containing 2,5-bis-dithienyl-1H-pyrrole (SNS)-donor and 1,8 naphthalimide-acceptor (SNS–NI) as a subunit. The electrochemical and optical properties were investigated via cyclic voltammetry (CV), UV–Vis absorption and fluorescence emission measurements, respectively. Besides, electrochromic performance of poly(SNS–NI) has been compared to the both the film preparation method and poly(1-phenyl-2,5-dithiophen-2-ylpyrrole) [poly(SNS–P)] as a standard polymer. In the poly(SNS–NI), yellow color of the polymer film at neutral state converted to green and then dark blue upon the polymer film fully oxidized in the positive regime. SNS–NI polymer film prepared via spin casting process exhibits a high contrast ratio in the near-IR region (ΔT% = 56% at 890 nm), a response time of about 1 s, high coloration efficiency (299 cm² C⁻¹) and retained its performance by 98.6% even after 5000 cycles. Finally, the results clearly indicate that both electronic nature of the molecule and film preparation method have a major impact on electrochromic performance of these polymers.     

Morphology effect on the electrochromic and electrochemical performances of NiO thin films

NiO thin films on ITO substrate were prepared by chemical bath deposition (CBD) and sol–gel method, respectively. The microstructure and morphology of the NiO films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both the films have polycrystalline cubic NiO, but have distinct morphology. The CBD NiO thin film with a highly porous structure exhibited a noticeable electrochromic performance. The variation of transmittance was high up to 82% at 550 nm and the coloration efficiency (CE) was calculated to be 42 cm² C⁻¹. The sol–gel NiO thin film with a smoothly compact structure presented 35% and 28 cm² C⁻¹ at 550 nm, respectively. The electrochemical properties of both the NiO thin films were investigated in 1 M KOH electrolyte by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The CV and EIS measurements revealed that the CBD NiO thin film had better electrochemical reversibility, higher reactivity and reaction kinetics due to its highly porous structure.     

Electrosynthesis and characterization of an electrochromic material from poly(1,4-bis(2-thienyl)-benzene) and its application in electrochromic devices

1,4-Bis(2-thienyl)-benzene monomer is successfully synthesized via coupling reaction. Poly(1,4-bis(2-thienyl)-benzene) (PBTB) is electrochemically synthesized and characterized. Resulting polymer film has distinct electrochromic properties. Its application in electrochromic devices (ECDs) is discussed. PBTB is switched between yellow in the neutral state and green in the oxidized state. Electrochromic switching of PBTB film is performed and the polymer film shows a maximum optical contrast (ΔT %) of 44.8% at 610 nm in visible region with a response time of 1.6 s. The coloration efficiency (CE) of PBTB is calculated to be 162 cm² C⁻¹. Electrochromic device (ECD) based on PBTB and poly(3,4-ethylenedioxythiophene) (PEDOT) is also constructed and characterized. Maximum contrast (ΔT %) and switching time of the device are measured as 29.5% and 0.43 s at 628 nm. The CE of the device is calculated to be 408.9 cm² C⁻¹. Clear change from green (at neutral state) to blue color (at full oxidized state) of this ECD is demonstrated with reasonable cycle life.     

Nanocrystalline NiO thin film anode with MgO coating for Li-ion batteries

The nanocrystalline NiO thin films with the mean size of 30 nm are prepared by pulsed laser reactive ablation in an oxygen ambient and subsequent coated by MgO on the NiO film surface. As compared with bare NiO, coated NiO film electrode heat-treated at 500 °C exhibits excellent structural stability and electrochemical performance. Excellent electrochemical performance, a reversible capacity as high as 650 mAh/g in the range 0.01–3.0 V at high discharge rate of 2C with a high capacity retention up to 150 cycles, could be achieved with MgO-coated NiO films. Preliminary electrochemical cycling measurements show that capacity retention with capacity fading for bare NiO and MgO-coated NiO film electrodes are 0.43 and 0.28% per cycle, respectively, at the discharge rate of 2C after 150 cycles. This result is related to good structural stability of the MgO-coated NiO film as verified by cyclic voltammetric (CV) measurement and scanning electron microscopy (SEM) analysis.     

Kinetics of hydrogen oxidation reaction on Nafion-coated Pt/C electrodes under high overpotentials

The influences of the Nafion film thickness and Pt loading on the kinetics of the hydrogen oxidation reaction on Nafion-coated 20 wt% Pt/C electrodes immersed in 0.5 M H₂SO₄ were investigated using a rotating disk electrode configuration. The coating of a Nafion film (8 μm) had a negligible effect on the electrochemical surface area of an electrode. The kinetic parameters were estimated at an overpotential of 0.4 V; the values obtained were shown to vary with the method of data treatment. The diffusional resistance for H₂ in the Nafion film was negligible when the film was thinner than 0.2 μm. The permeability of H₂ in the Nafion film ranged from 2.4 × 10⁻⁵ to 4.8 × 10⁻⁵ mM cm²/s. The error analysis demonstrated that the apparent kinetic current estimated was resulted from experimental errors, instead of resulting from a chemical process as proposed by some previous investigators.     

Preliminary analysis of the 1H-NMR and 13C-NMR spectra of poly(2,5-dimethyl-3-vinylfuran)

Summary The title monomer was synthesized by dehydration of the corresponding alcohol. The monomer was polymerized under free radical conditions and H- and ¹³C-NMR spectra were recorded and analyzed. The spectra displayed several resonances with sensitivity to polymer stereochmistry and analysis of these resonances showed poly(2,5-dimethyl-3-furan) to be an atactic polymer.     

二芳基乙烯类光致变色化合物的合成及其光电性质研究

在氮气及-78℃条件下,合成了两种二芳基乙烯类光致变色化合物1,2-双(2-甲基-5-(4-N,N-二甲氨基苯基)噻吩-3-基)全氟环戊烯(Ⅰa)和1,2-双(2-甲基-5-萘基噻吩-3-基)全氟环戊烯(Ⅱa),通过紫外-可见吸收光谱、荧光光谱、循环伏安法对其光谱特性和电化学性质进行了初步研究。在254nm紫外光照射下,Ⅰa和Ⅱa的氯仿溶液均由无色变为蓝色,最大吸收峰分别为620和570nm,在适当波长可见光照射下,均从有色态返回到无色态。通过UV-Vis光谱考察了这两种二芳基乙烯类化合物在溶液中的光致变色反应的动力学特征,实验结果表明,二芳基乙烯类光致变色化合物的闭环反应属于零级反应,开环反应为一级。电化学研究表明,在溶液中,Ⅰa和Ⅱa可发生不可逆的阳极氧化反应。     

A soluble conducting polymer: 1-Phenyl-2,5-di(2-thienyl)-1H-pyrrole and its electrochromic application

A thiophene-functionalized monomer 1-phenyl-2,5-di(2-thienyl)-1H-pyrrole (PTP) was synthesized. The chemical polymerization of PTP (CPTP) was realized by using FeCl₃ as the oxidant. The structures of both the monomer and the soluble polymer (CPTP) were investigated by Nuclear Magnetic Resonance (¹H and ¹³C NMR) and Fourier Transform Infrared (FTIR). The average molecular weight of the chemically synthesized polymer was determined by gel permeation chromatography (GPC) as Mn = 7.2 × 10³. The electrochemical oxidative polymerization of PTP was carried out via constant-potential electrolysis. Characterizations of the resulting polymer were done by cyclic voltammetry (CV), FTIR, Scanning Electron Microscopy (SEM) and UV-vis Spectroscopy. The conductivity of sample was measured by four-probe technique. Moreover, the spectroelectrochemical and electrochromic properties of the polymer film were investigated. Spectroelectrochemical analysis of P(PTP) revealed electronic transitions at 413, 577 and 884 nm corresponding to π-π^* transition, polaron, and bipolaron band formations, respectively. Kinetic studies evaluated the switching ability of the P(PTP); the percent transmittance T% was found as 27%. The homopolymer of PTP was used to construct dual-type polymer electrochromic devices (ECDs) against poly(3,4-ethylenedioxythiophene) (PEDOT). Spectroelectrochemistry, electrochromic switching and open circuit stability of the devices were investigated.     

Synthesis,spectroscopy, and electrochemical investigation of new conjugated polymers containing thiophene and 1,3,4-thiadiazole in the main chain

Novel photoluminescent donor–acceptor poly(p-phenylenevinylene)-type conjugated polymers containing thiophene and 1,3,4-thiadiazole units in the main chain were synthesized from 2,5-bis(5-bromomethyl-2-thienyl)-1,3,4-thiadiazole and 1,3/1,4-benzenedialdehyde by Wittig–Horner reaction. The synthesized polymers were characterized by the use of thermal analysis and spectroscopic (infrared, UV-visible absorption, and photoluminescence) measurement. The resultant material exhibited bluish green, green, and orange fluorescence in their solution and thin film and solid forms, respectively. The redox property of the polymers has also been studied by cyclic voltammetry. The optical and electrochemical studies reveal that these novel polymers are new promising materials for the development of efficient polymer light-emitting diodes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Corrosion studies on electrochemically deposited PANI and PANI/epoxy coatings on mild steel in acid sulfate solution

The corrosion behavior of mild steel and mild steel covered by electrochemically deposited (a) polyaniline (PANI) film, (b) epoxy coating and (c) PANI/epoxy coating system in 0.1 M sulfuric acid solution were investigated by electrochemical impedance spectroscopy (EIS). Electrochemical deposition of PANI film was performed from aqueous solution of 0.5 M sodium benzoate and 0.1 M aniline at constant current density of 1.5 mA cm⁻². Epoxy coatings on mild steel and mild steel modified by PANI film were deposited at constant voltage. It was shown that thin PANI film had provided good corrosion protection of mild steel in 0.1 M sulfuric acid solution, and could be used for modification of mild steel prior to epoxy coating deposition. The increased corrosion protection of mild steel by PANI/epoxy coating system in the same solution was obtained.     

Processable electrochromic and fluorescent polymers based on N-substituted thienylpyrrole

A new series of processable conducting polymers based on thienylpyrrole was synthesized by electrochemical polymerization of 1-(1-naphthyl)-2,5-di(thiophen-2-yl)-1H-pyrrole, 1-(2-naphthyl)-2,5-di(thiophen-2-yl)-1H-pyrrole, 1-(9H-fluoren-2-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole and 1-(benzo-15-crown-5)-2,5-di(thiophen-2-yl)-1H-pyrrole. The corresponding polymers have very well-defined and reversible redox processes in both organic and aqueous solutions. Furthermore, they exhibit multielectrochromic behavior: yellow in the neutral state, green and blue in the intermediate state and violet in the oxidized state. The polymer products are soluble in organic solvents and all of them are fluorescent.     

A novel electrochromic and fluorescent polythienylpyrrole bearing 1,1′-bipyrrole

A novel conducting polymer was successfully synthesized via electropolymerization of 1-(1H-pyrrol-1-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole. The electrochemical and electro-optical properties of the corresponding polymer, which was the first example of polymer containing 1,1′-bipyrrole units, were elaborated using electroanalytical and spectroscopic techniques. Cyclic voltammograms and electro-optical studies showed that the polymer has a stable and well-defined reversible redox process as well as electrochromic behavior. The processable polymer film also possessed a yellowish orange light emitter property.