A polythiophene derivative bearing TEMPO as a cathode material for rechargeable batteries

A polythiophene derivative bearing TEMPO radical was synthesized by oxidative chemical polymerization of its monomer. The polymer had a high spin density (2.05 × 10²¹ spins/g of polymer). CV studies of the polymer showed that the electrochemical redox reaction of the TEMPO radicals were completely reversible. We demonstrated, for the first time, construction and charge/discharge characteristics of an organic radical battery utilizing a TEMPO bearing polythiophene based cathode material. The battery had an initial specific discharge capacity of 79 A h/kg (87% of the theoretical capacity) and an average output voltage of 3.6 V. The specific energy capacity initially discharged was 268 W h/kg.     

Electrosynthesis of structured derivated polythiophenes: Application to electrodeposition of latex particles on these substrates

Synthesis of super-structured polymers is a great challenge because these entities could present a large choice of applications. Synthesis and electropolymerisation of thiophene derivatives are reported. Star-shaped 3D molecules are chosen because these structures ensure a high electronic conductivity. Three-dimensional structures could also assist the conductivity. 1,3,5-tris[5-(2,2′-dithienyl)]benzene 1, tris(2,2′-dithienyl)methylcarbinol 2, tris(5(2,2′:5′2″-terthienyl)methylcarbinol 3 are synthetised by different ways. UV and IR analysis are reported along with an AFM examination of the film. The first attempt of latex particle deposition on the film is also reported showing promising results in view of surface functionalisation.     

Infrared and photoelectron spectroscopy study of vapor phase deposited poly (3-hexylthiophene)

Poly (3-hexylthiophene) (P3HT) was thermally evaporated and deposited in vacuum. Infrared spectroscopy was used to confirm that the thin films were indeed P3HT, and showed that in-situ thermal evaporation provides a viable route for contaminant-free surface/interface analysis of P3HT in an ultrahigh-vacuum (UHV) environment. Ultraviolet photoelectron spectroscopy (UPS) as well as X-ray photoelectron spectroscopy (XPS) experiments were carried out to examine the frontier orbitals and core energy levels of P3HT thin films vapor deposited in UHV on clean polycrystalline silver (Ag) surfaces. UPS spectra enable the determination of the vacuum shift at the polymer/metal interface, the valence band maximum (VBM), and the energy of the π-band of the overlayer film. The P3HT vacuum level decreased in contrast to that of the underlying Ag as the film thickness increased. XPS and UPS data confirmed the chemical integrity (stoichiometry) of the polymer at high coverage, as well as the shift of the C 1s and S 2p binding energy peaks and the secondary-electron edge with increasing film thickness, indicating that band bending is present at the P3HT/Ag interface and that the measured onset of the valence band is about 0.8 ± 0.05 eV relative to the Fermi level.     

Characterization and properties of a polythiophene with a malonic acid dimethyl ester side group

A new polythiophene derivative bearing a malonic acid dimethyl ester substituent attached to the 3-position of the repeat unit has been prepared by chemical oxidative-coupling polymerization. The chemical structure of poly(2-thiophen-3-yl-malonic acid dimethyl ester) has been analyzed by FTIR and ¹H NMR spectroscopy and, additionally, the distribution of the head-to-tail and head-to-head diads arising from polymerization was found to be a 75-25%. The glass transition temperature identified for this polymer was 17.6 °C lower than that recently determined for a closely related polythiophene derivative, in which the ester substituent arose from acrylic acid rather than from malonic acid. On the other hand, the electrical conductivity of the new material, which was soluble in polar solvents but not in water, was higher than that typically found for poly(3-alkylthiophene) derivatives. Ab initio quantum mechanical calculations on simple model compounds were used to predict the regiochemistry of the polymer chain, which was in excellent agreement with the experimental observation, and the conformational preferences of both the inter-ring dihedral angle and the bulky side group. Interestingly, calculations predict that the inter-ring dihedral angles adopt a syn-gauche conformation rather than the anti-gauche arrangement typically found in substituted polythiophenes. Thus, in this case the former conformation reduces the strong repulsive interactions induced by the bulky substituent. The lowest π-π^∗ transition energy derived from calculations on an idealized molecular model is in agreement with the experimental estimation determined using UV-vis spectroscopy. This electronic property is significantly higher for poly(2-thiophen-3-yl-malonic acid dimethyl ester) than for other substituted polythiophene derivatives, which is consequence of the geometrical distortions induced by bulky side group.     

导电性高聚物化学的进展

对近年来国内外导电高聚物在合成,结构与性能的关系,导电机理及其应用等方面进行了介绍和评述。     

电化学合成聚噻吩薄膜提高光伏电池的开路电压

以铟锡氧化物(ITO)/聚(3,4-亚乙二氧基噻吩)-聚(苯乙烯磺酸)(PEDOT:PSS)为工作电极,采用电化学沉积法,直接在其上形成聚3-己基噻吩(P3HT)薄膜。其紫外可见吸收光谱的峰值约位于410nm处,吸收边延至610nm处,禁带宽度为2.04eV。测得其最高占有分子轨道(HOMO)能级为-5.21eV,而化学合成P3HT的HOMO能级为-5.02eV,这可能源于电化学合成聚噻吩的规整度比化学合成的要高。原子力显微镜AFM形貌结果表明电化学合成的P3HT中噻吩分子排列紧密,循环伏安扫描表明此P3HT薄膜的电化学性质稳定。采用该电化学合成的聚噻吩与富勒烯衍生物[6,6]-苯基-C61-丁酸甲酯(PCBM)复合而成的光伏电池的开路电压高达0.76V,这主要源于电化学合成聚噻吩HOMO能级的降低,因而揭示了提高光伏电池开路电压的新途径。     

STRUCTURAL ANALYSIS AND ENVIRONMENTAL STABILITY OF POLYFLUORINATED GROUP SUBSTITUTED POLYTHIOPHENES

Electrochemical polymerization of 3-fluoroalkoxy and 3-fluoroether thiophenes givespolymers with relatively high molecular weights and good processibility. Investigationof these polymers by means of GPC indicates that an increase in the number of fluorineatoms in the fluorinated group results in a decrease in degree of polymerization of thepolymers in the same polythiophene series. As shown by NMR and FTIR, the polyfluo-rinated group substituted polythiophenes have regular 2, 5-coupling in their main chains.The SEM micrographs of the polymer films exhibit that polymer (1)-poly [3-2, 2, 3, 3-tetrafluoro-propoxy) thiophene] possesses more regular structure than the other polymersdo. Substitution of polythiophenes by fluorinated groups leads to the polymers with highelectric, electrochemical and thermal stability.     

Electrochemical preparation of a soluble conducting aniline-thiophene copolymer

A new of soluble sulfonated conductive copolymer has been synthesized by electrochemical oxidation in the presence of anhydrous FSO₃H. The sulphur-to-nitrogen ratios indicated that copolymers were formed in addition to the incorporation of groups into polymeric backbone. The sulfonated copolymer films have better solubility in DMSO and KOH. The conductivity of the copolymer films increases with the increase in the number of thiophene rings in the polymeric backbone. Copolymer films synthesized were investigated by cyclic voltammetry, UV-visible, FT-IR and ¹H-NMR spectroscopy, dry conductivity and intrinsic viscosity measurements, elemental analysis and SEM pictures.     

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.     

Anodic polymerization of dithienosilole and electroluminescent properties of the resulting polymer

Anodic oxidation of 2,6-bis(trimethylsilyl)-4,4-di(p-tolyl)dithienosilole gave a dark orange solid polymer with a small band gap. The spectral analysis of the polymer indicated that decomposition of the dithienosilole ring system had competed the polymerization to an extent. This, however, could be suppressed by optimizing the reaction conditions. Applications of the spin-coated polymer films to electroluminescent materials are described.