Theoretical Investigation on the Luminescent Properties of Polyfluorene and Poly(fluorene-co-thiophene)

The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory（TD-DFT） and ZINDO were employed to study the lowest excitation energies（Egs） and the absorption and emission spectra of the oligomers of polyfluorene（PF） and poly（fluorene-co-thiophene）（PFT）. By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths of the corresponding polymers were obtained. The IPs, EAs and 2abs of the polymers were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero（I/n=0）. The outcome shows the decreased dihedral angle between fluorene and thiophene units in the PFT compared to that between fluorene units in the PF results in the increased efficient conjugation of PFT. These cause both the maximal absorption and emission wavelengths of PFT red-shifted compared with those of PF.

ELECTROCHEMICAL COPOLYMERIZATION OF DIBENZOFURAN AND 3-METHYLTHIOPHENE IN BORON TRIFLUORIDE DIETHYL ETHERATE

The copolymerization of dibenzofuran(DBF)and 3-methylthiophene(MET)was successfully achieved electrochemically by direct anodic oxidation of the monomer mixtures in boron trifluoride diethyl etherate.The effects of applied polymerization potential and the monomer concentration ratios on the copolymerization were investigated by linear sweep voltammetry and cyclic voltammetry(CV).The structure of copolymer films were investigated by UV-Vis,infrared spectroscopy,thermal analysis.As-formed novel copolymers own...

Synthesis and Bio-activities of Poly(3,4-ethylenedioxythiophene)(PEDOT)/Poly(styrene sulfonate)(PSS)/Gelatin Layer on Indium Tin Oxide(ITO)-coated Glass

Poly （3, 4-ethylenedioxythiophene） （PEDOT）, together with its dopes, such as poly （styrene sulfonate） （PSS）, has been acknowledged to have a wide range of biomedical applications as an important conducting polymer. In this study, gelatin can be polymerized into PEDOT/PSS polymers on indium tin oxide （ITO）-coated glass. PEDOT/PSS/gelatin layer on ITO-coated glass significantly decreases electrochemical impedance spectroscopy （EIS） and increases charge delivery capacity relative to the gelatin layer and bare ITO- coated glass, comparable to the PEDOT/PSS layer on ITO-coated glass. PEDOT/PSS/gelatin layer on ITO- coated glass enhances pheochromocytoma （PC 12） cell affinity, possesses a high biocompatibility and promotes PC 12 cell growth by delivery of electrical stimulation. These results suggest that gelatin can be incorporated into the PEDOT/PSS polymers through electrochemical polymerization and the PEDOT/PSS/gelatin layer on ITO-coated glass possesses high electrochemical and biological activities.

An asymmetric membrane of polyimide 6FDA-BDAF and its pervaporation desulfurization for n-heptane/thiophene mixtures

Polyimide（PI） is a type of important membrane material. A soluble polymer was synthesized from 4,4′-（hexafluoroisopropylidene） diphthalic anhydride（6FDA） and 2,2-bis[4-（4-aminophenoxy） phenyl] hexafluoropropane（BDAF） by the two-step polymerization method. The polymer was proved to be polyimide 6FDA-BDAF by the Fourier transform infrared（FT-IR）, the 1H-NMR and ^（19）F-NMR spectra. An asymmetric membrane was prepared with the synthesized polyimide 6FDA-BDAF, it was porous in the 50 μm height bulk and dense in a 3–5 μm height surface. The membrane was used to separate n-heptane/thiophene mixtures by pervaporation with sulfur（S） contents from 50 to 900 μg g^（–1）. The total flux was enlarged from 7.96 to 37.61 kg m^（–2） h^（–1） with temperature increasing from 50 to 90°C. The membrane＇s enrichments factor for thiophene were about 3.13 and dependent on the experimental conditions. The experimental results demonstrated that polyimide 6FDA-BDAF would be a potential membrane material for desulfurization and controlled release of the S-containing fertilizer.

Photochemical reactions of poly(3-butoxythiophene-2,5-diyl) with chloroform

Photochemical reactions of poly(3-butoxythiophene-2,5-diyl) with chloroform under irradiation with light were studied. The reactions were separately carried out under air, oxygen, and nitrogen. The obtained results showed that this reaction belongs to the pseudo-first-order reaction with a rate constant kobs of 1.4×10?5 s?1 at room temperature. The presence or absence of air, oxygen, and nitrogen did not have obvious effects on the reaction rate under irradiation with light.

Synthesis, Crystal Structure and Fluorescent Property of a New One-dimensional Cadmium(Ⅱ) Coordination Polymer Based on 3,4-Thiophenedicarboxylic Acid and 1,10-Phenanthroline

A new cadmium（Ⅱ） polymer [Cd（tdc）（Phen）]n 1 （H2tdc = thiophene-3,4-dicar-boxylic acid, Phen = 1,10-phenanthroline） was synthesized under hydrothermal conditions. The compound crystallizes in the triclinic system, space group P , with a = 7.3150（10）, b = 10.3598（14）, c = 10.8784（15） , α = 82.2740（10）, β = 72.9730（10）, γ = 80.236（2）°, V = 773.68（18） 3, Z = 2, Mr = 462.74, Dc = 1.986 Mg/m3, μ = 1.58 mm-1, F（000） = 456, the final R = 0.0218 and wR = 0.0465 for 3361 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The compound presents a one-dimensional （1-D） double-stranded structure and exhibits fluorescent emission at room temperature. Furthermore, infrared spectroscopy, elemental analyses, thermogravimetric analysis and powder X-ray diffraction properties of the compound are also investigated.

Separation/Enrichment of Copper and Silver Using Titanium Dioxide Nanoparticles Coated with Poly-Thiophene and Their Analysis by Flame Atomic Absorption Spectrophotometry

We report on the use of titanium dioxide nanoparticles (NPs) coated with poly-thiophene for the preconcentration of copper and silverions. The NPs were prepared by first modifying the surface of TiO2 NPs with vinyl groups and then copolymerizing them with vinyl thiophen. The resulting TiO2-polythiophene core-shell NPs were characterized by thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X-ray diffraction. The experimental conditions such as pH value, adsorption and desorption time, type, concentration and volume of the eluent, break through volume, and effect of potentially interfering ions were optimized. The ions were then desorbed with hydrochloric acid and determined by FAAS. The limits of detection are 0.4 and 1.2 μg·L_1 for Cu(II) and Ag(I), respectively, and recoveries and precisions are >98.0%

Overoxidized poly(3,4-ethylenedioxythiophene)-gold nanoparticles-graphene-modified electrode for the simultaneous detection of dopamine and uric acid in the presence of ascorbic acid

An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles(Au NPs),and electrochemically reduced graphene oxide(ERGO)was prepared on a glassy carbon electrode(GCE)(OPEDOT-Au NPs-ERGO/GCE)through homogeneous chemical reactions and heterogeneous electrochemical methods.The morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.The electrochemical properties of the OPEDOT-Au NPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(III)chloride redox probe systems.This modified electrode shows excellent electro-catalytic activity for dopamine(DA)and uric acid(UA)under physiological p H conditions,but inhibits the oxidation of ascorbic acid(AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100μM and UA concentrations of approximately 20-100μM were used.The detection limits(S/N=3)for DA and UA were 1.0 and 5.0μM,respectively,under physiological conditions and in the presence of 1.0 m M of AA.This developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7%to 105.0%were observed.This work demonstrates that the developed OPEDOT-Au NPs-ERGO ternary nanocomposite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.

SYNTHESIS AND CHARACTERIZATION OF PHENOTHIAZINE-BASED PPV-TYPE COPOLYMERS CONTAINING FLUORENE AND THIOPHENE MOIETIES

Copolymers of fluorene-co-phenothiazine （ P1） and th iophene-co-phenothiazine （ P2 ） were prepared respectively by Wittig reaction. The synthesis, photo-physical and electroluminescent properties of the resulting polymers were analyzed by FT-IR, GPC, IH-NMR, UV-Vis, Photoluminescence （PL）, Electroluminescence （EL） and Cyclic Voltammetry （CV）. Their single layer devices with configuration of lTO/polymers/Ca/Al were studied. GPC results revealed the weight-average molecular weight （Mw） was 3.0×10^3 and 5.4×10^3, respectively. The device with a single layer structure of ITO/P1/Ca/Al emits green light with the maximum peak at 552nm. However, the device with a single layer structure of ITO/P2/Ca/Al emit red light with the maximum peak at 616nm.

A Study on Preparation and Use of Nano Poly Pyrrole and Nano Poly (3,4-Ethylenedioxythiophene) Coated Glassy Carbon Electrode For The Determination of Antihistamine in Pharmaceutical and Urine Sample

Pheniramine maleate (PA), an antihistamine, was determined by Differential Pulse Stripping voltammetry using nano polypyrrole (Ppy) and nano poly(3,4-ethylenedioxythiophene) (PEDOT) modified glassy carbon electrodes. The cyclic voltammetric behavior of pheniramine was studied in aqueous acidic, neutral and alkaline conditions. One well-defined oxidation peak was observed in the cyclic voltammograms at all pHs. The influence of pH, scan rate and concentration revealed irreversible electron transfer and the oxidation was diffusion controlled adsorption. The SEM analysis confirmed good accumulation of PA on the electrode surface. A systematic study of influence of various experimental parameters that affect the stripping voltammetric response was carried out and the maximum peak current conditions were arrived at. Calibration was made under maximum peak current conditions. The range of study was 0.05 to 0.4 μg/mL on Ppy/GCE and 0.025 to 0.4μg/mL on PEDOT/GCE and the lower limit of determination were 0.035μg/mL on Ppy/GCE and 0.016μg/mL on PEDOT/GCE. The suitability of the method for the determination of PA in pharmaceutical preparations and urine samples was also ascertained.

Synthesis of Novel Covalent-linked Linear Porphyrin-Thiophene Copolymers

Linear porphyrin-thiophene copolymers were synthesized by linking 5, 15-positions of porphyrin with tetrathiophene or bithiophene moieties for preparing conducting polymer. 2,8,12,18-tetraethyl-3,7,13,17-tetramethyl-5, 15-dithienylporphyrin4a (45.1%), 5, 15-di-bithienyl- 2,8,12,18-tetraethyl-3, 7, 13, 17-tetramethylporphyrin4b (61. 2%) and their metal complexes were also reported in high yields (>90%) as the monomers. 5, 15-di-bithienylporphyrin and its metal complexes could be polymerized by oxidation using FeCl3 as oxidant. However, 5,15-dithienylporphyrin and its metal complexes can not be polymerized by same reaction. Their polymers were synthesized by electrochemical oxidation on the gold-plate electrode. The structures of copolymers were identified by elemental analysis and IR spectra. And the conductivity of poly 5,15-di-bithienylporphyrin was measured to reach over 1.0× 10?6S/cm. Key words organic conductor - thienylporphyrin - porphyrin-thiophene copolymer - electropolymerization CLC number O 62 Foundation item: Supported by the National Natural Science Foundation of China (29872033, 20272046)Biography: CHEN Zhang-ping (1946-), male, Professor, research direction: porphyrin chemistry.

Hydrothermal Synthesis and Crystal Structure of a New Three-dimensional Co(Ⅱ) Coordination Polymer Based on 2,3-Thiophenedicarboxylic Acid

A new Co（ll） polymer [Co（tdc）（l,4-bimb）]n 1 （H2tdc = thiophene-2,3-dicarboxy- lic acid, 1,4-bimb -- 1,4-bis（imidazol-1 ＇-yl）butane） was synthesized under hydrothermal conditions The compound crystallizes in the monoclinic system, space group C2/c with a = 15.643（9）, b = 8.839（5）, c=12.952（7） A, β = 105.964（6）°, V= 1721.8（16） A3, Z = 4, Mr = 419.32, Dc= 1.618 Mg/m3,μ = 1.149 mm-1, F（000） = 860, the final R = 0.0243 and wR =0.0613 for 1460 observed reflections with I 〉 2σ（I）. The compound presents a three-dimensional （3D） network extended by both tdc2- anions and 1,4-bimb ligands in which the tdc2- anions employ a chelating coordination mode. From the topology point of view, the structure could be described as a 3D 4-connected 65.8 CdSO4-type net. Infrared spectroscopy, elemental analyses, thermogravimetric analysis and powder X-ray diffraction properties of 1 are also investigated.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL STYRYLTHIOPHENE MONOMER AND CORRESPONDING POLYURETHANE FOR NLO MATERIALS

A novel monomer, (trans)-7-[4-N,N-(di-beta-hydroxyethyl) amino-benzene]-ethenyl-3,5-dinitrothiophene (HBDT), was synthesized and characterized. The details of synthesizing the monomer and prepolymer, polyurethane with the monomer covalently incorporated are presented. The prepolymer and polyurethane exhibited good solubility in common organic solvents. Molecular nonlinear optical properties of the monomer (HBDT) substituted thiophene based stilbenes is presented.

NOVEL RED LIGHT-EMITTING POLYMERS BASED ON 2,7-CARBAZOLE AND THIOPHENE DERIVATIVES

A series of conjugated copolymers derived from 9-ethylhexyl-2,7-carbazole(Cz)and 4,7-di(4-hexylthien-2-yl)- 2,1,3-benzothiadiazole(DHTBT)was synthesized by Suzuki polycondensation.The photo-and electro-luminescent properties of these polymers were investigated.Efficient energy transfer from the Cz segment to the DHTBT unit occurs even if the DHTBT content as low as 1 mol%.PL emission was red-shifted significantly from 645 nm to 700 nm with the increase in DHTBT content by 1-50 mol%.PL efficiencies decreased...

Solvent and Temperature Effects on Spectral Properties of Two Poly(3-alkyl)thiophene Derivatives

Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as catalyst in chloroform. While both polymers in pure chloroform solution have maximum absorption at approximately same wavelength of 440nm, they behave differently with respect to changes observed on their UV-visible and photoluminescence spectra when the quality of the poor solvent is changed in good solvent (chloroform) / poor solvent (methanol) mixtures. With increasing volume fraction of methanol in mixtures, the absorption spectra of P3HT and P3DT red-shift, peaking at maximum wavelength of 495nm (P3HT) and 510nm(P3DT). Furthermore, the absorption spectra of the two polymers in chloroform blue-shift as the temperature rises. P3HT shows 4.73nm blue-shifts at 50℃ in contrast to the case at 20℃, while P3DT blue-shifts about 5.04nm. The photoluminescence spectra of the two polymers in mixed solution are also investigated, which show that the luminescence spectra shift to longer wavelength with an accompanying drop in the PL intensity as methanol is increased. The absorption and emission spectra of the two polymers in a poor solvent and a thin film are similar, which indicate that a similar longer conjugation length in the two cases. It could conclude that the polymers exist almost the same conformations and aggregations in both a poor solvent and a thin film. P3DT exhibits more sensitive spectra properties (big red-shifts in both absorption and luminescence spectra in poor solvents and large blue-shifts at high temperature) with contrast to P3HT, which imply that long side alkyl may improve the chromic properties of the polymer.

DOPING LEVEL INCREASE OF POLY(3-METHYLTHIOPHENE)FILM DURING ELECTROCHEMICAL POLYMERIZATION PROCESS

The Raman spectra of poly(3-methylthiophene) (PMeT) films with different thicknesses, which have been electrochemically deposited on a flat stainless steel electrode surface by direct oxidation of 3-methylthiophene in boron trifluoride diethyl etherate (BFEE) at a constant applied potential of 1.38 V (versus SCE), have been investigated by excitation with a 633-nm laser beam. The spectroscopic results demonstrated that the doping level of PMeT film was increasing during film growth. This finding was also confirmed by electrochemical examination. Moreover, the Raman bands assigned to radical cations and dications in doped PMeT films were found approximately at 1420 and 1400 cm(-1), respectively. Radical cations and dications coexist on the backbone of PMeT as conductive species and their concentrations increase with the increase of doping level. Successive cyclic voltammetry was proved to be an effective approach to improving the doping level of as-grown thin compact PMeT film.

SYNTHESIS OF SOLUBLE POLY(3-HEXYL-2,5-THIENYLENE VINYLENE) FROM THIOPHENE

Soluble poly(3-hexyl-2,5-thienylene vinylene) (PHTV) was readily synthesized from thiophene in a yield better than that of the precursor method to prepare poly(thienylene vinylene) (PTV). The bandgap of the polymer is about 1.8 eV, which is comparable with that of PTV. Owing to the introduction of alkyl side groups onto the backbone of the polymer, it can be dissolved in common organic solvents such as chloroform, THF and toluene. The synthesis of soluble PHTV is a very important approach to preventing oxidation and to improving the properties and the processbility of the PTV. The existence of alkyl side groups in PHTV does not affect its, bandgap and thermal properties as compared with PTV. After doping with FeCl3, the conductivity of PHTV is as high as 1.1 x 10(-2) S/cm. The soluble PHTV can be easily transformed into thin film with much better quality than that of the PTV film prepared by the traditional precursor method, which is very important for fabricating devices with good properties.

High Performance Polymer Field-Effect Transistors Based on Thermally Crosslinked Poly(3-hexylthiophene)

The performance of polymer field-effect transistors is improved by thermal crosslinking of poly(3-hexylthiophene),using ditert butyl peroxide as the crosslinker.The device performance depends on the crosslinker concentration significantly.We obtain an optimal on/off ratio of 105 and the saturate field-effect mobility of 0.34 cm2V−1s−1,by using a suitable ratios of ditert butyl peroxide,0.5 wt%of poly(3-hexylthiophene).The microstructure images show that the crosslinked poly(3-hexylthiophene)active layers simultaneously possess appropriate crystallinity and smooth morphology.Moreover,crosslinking of poly(3-hexylthiophene)prevents the transistors from large threshold voltage shifts under ambient bias-stressing,showing an advantage in encouraging device environmental and operating stability.

Chemical Oxidative Synthesis and Conductivity of Poly(3,4-ethylenedioxythiophene)

[Objective] This paper was to introduce the chemical oxidative synthesis process, properties and test methods of 3,4-ethylenedioxythiophene(EDOT). [Method] The poor water solubility of EDOT was solved by using polyethylene glycol 20000(PEG) as the surfactant. The monomer was polymerized by chemical oxidative synthesis. The product was analyzed and verified by infrared spectrum, X-ray diffraction, ultraviolet-visible absorption spectra.[Result] The conductivity of the product was the best when the mass ratio of PEG and EDOT was 1∶1. The effects of oxidant dose and reaction time on the conductivity and yield of the product showed certain regularity. [Conclusion] EDOT could be polymerized by PEG and FeCl3, and the polymerization product was PEDOT.