A molecular dynamics study of ion migration in a doped electroactive polymer

Simulating the \hbox{BF}_{4}^{-} -doped poly(3-octylthiophene) lattice by molecular dynamics results in a structure in which dopant ions intercalate as a sandwich between thiophene rings on adjacent polymer chains. The ions occupy sites in channels parallel to the polymer main chain, which retains a high degree of planarity in contrast to the pristine (undoped) polymer. Even when lattice imperfections are created by expanding the cell, Coulomb forces ensure that the intercalation features containing the dopant channels are largely retained. On applying electric fields in the principal directions of the 'perfect lattice' it is found that the ions migrate most readily along the ion-channel directions (the lattice c axis), leaving the lattice undisturbed. Although higher electric fields cause dopant migration to occur perpendicular to the channel directions they destroy the intercalated lattice. In the reduced-order lattice regions substantial motion of the ions are predicted at a critical value of the lattice parameter.     

A novel amperometric glucose biosensor based on reconstitution of glucose oxidase on thiophene-3-boronic acid polymer layer

The biosensor was constructed for determination of glucose by using glucose oxidase enzyme immobilized on poly(thiophene-3-boronic acid) (PTBA). Boronic acid functionalized polythiophene layer was obtained by electrochemical polymerization of Thiophene (Th) and thiophene-3-boronic acid (TBA) with different monomer rations. The reconstitution of the apo-glucose oxidase (apo-GOx) on a complexed flavin adenine dinucleotide (FAD) linked to polythiophene boronic acid (PTBA) monolayer yields an electrically contacted enzyme monolayer. The GOx-reconstituted enzyme electrode exhibited excellent electrocatalytic activities toward the reduction and oxidation of hydrogen peroxide as well. The PTBA/FAD/GOx biosensor shows an excellent performance for glucose at +0.4 V with a high sensitivity (2.14 μA/mM) and lower response time (～5 s) in a wide concentration range of 0.5–18 mM (correlation coefficient of 0.9952). Furthermore, the effects of applied potential, pH, temperature, electroactive interference, stability and reusability of the biosensors were discussed.     

Sensitive and selective detection of aspartic acid and glutamic acid based on polythiophene-gold nanoparticles composite

In recent years, gold nanoparticles and water-soluble fluorescent conjugated polymers are promising materials in terms of their potential applications in a variety of fields, ranging from monitoring DNA hybridization to demonstrate the interaction between proteins, or detecting diseased cell, metal ions and small biomolecular. In order to exploit some new properties of the both, many attempts have been devoted to achieve nanoparticle-polymer composite via incorporating metal nanoparticle into polymer or vice versa, however, only few of them are put into practical application. In the present paper, we utilize the “superquenching” property of AuNPs to polythiophene derivatives for detecting aspartic acid (Asp) and glutamic acid (Glu) in pure water, and discuss the factors accounting for fluorescence quenching and recovery via modulating pH. Thus an exceptionally simple, rapid and sensitive method for detecting Asp and Glu is established with a limit of detection (LOD) is 32 nM for Asp and 57 nM for Glu, the linear range of determination for Asp is 7.5 × 10⁻⁸ M to 6 × 10⁻⁶ M and 9.0 × 10⁻⁸ M to 5 × 10⁻⁶ M for Glu. The system is applied to real sample detection and the results are satisfying. Otherwise the composite is very sensitive to pH change of solution, we expect it will be possible to use as pH sensor with wide range in the future.     

Electrosyntheses and characterization of polyalkylenedioxybenzenes

Direct anodic oxidation of 1,2-methylenedioxybenzene (MDOB) and 1,2-ethylenedioxybenzene (EDOB), analogues of 3,4-alkylenedioxythiophene and 3,4-alkylenedioxypyrrole, led to the formation of polyacetylene derivatives, poly(1,2-methylenedioxybenzene) (PMDOB) and poly(1,2-ethylenedioxybenzene) (PEDOB), on a platinum sheet in pure boron trifluoride diethyl etherate (BFEE). IR, ¹H NMR, ¹³C NMR and quantum chemistry calculations confirmed that the polymerization occurred at C(4) and C(5) position on the benzene ring of the monomer, making the main backbone of PMDOB and PEDOB similar to polyacetylene. Both dedoped PMDOB and PEDOB in DMSO solution showed good fluorescence properties with quantum yields of 0.13 and 0.27, emitting blue and green light under excitation of 365 nm, respectively. PMDOB showed electrochromic properties from grass green (doped) to light nacarat (dedoped). PEDOB changed it from bottle green (doped) to nacarat (dedoped). Doped PMDOB and PEDOB own electrical conductivities of 0.1 S cm⁻¹ and 0.17 S cm⁻¹, respectively.     

LOW POTENTIAL ELECTROPOLYMERIZATION OF ANISOTROPIC CONDUCTIVE POLYTHIOPHENE FILMS AND FABRICATION OF ELECTRICAL DEVICES

The complexation of thiophene with a Lewis acid with moderate acidity as a solvent, such as BF_3-ethyl ether (BFEE) remarkedly lowered the electrochemical polymerization potential. The positively chargedmetal surface of electrode in the process of electrochemical deposition enhanced the coordination interactionbetween π-electrons of thiophene unit and the metal, which makes thiophene rings lie parallel to the surfaceof electrode, resulting in a highly ordered polymeric structure. Because of the large intra-chain transferintegrals, the transport of charge is believed to be principally along the conjugated chains, which is muchgreater than the inter-chain hopping. The specific electrical resistance across the polythiophene film thicknessis more than 10~4 times than that along the surface plane of the film. In this paper we review the recentdevelopment of polymerization technique by low potential electrochemical method performed in our lab andseveral electrical devices in which the compact polythiophene films, such as anionic and cationic sieves, andlaminate film junction of undoped polythiophene derivatives were used.     

QCM-DNA biosensor based on plasma modified PT/TiO2 nanocomposites

A quartz crystal microbalance DNA biosensor based on plasma prepared polythiophene /titanium dioxide (PT/TiO₂) nanocomposite was developed for the detection of genetically modified organisms (GMOs). DNA hybridization was studied by quartz crystal microbalance (QCM) and cyclic voltammetry (CV) measurements. Single stranded DNA probes were immobilized on the PT/TiO₂ coated quartz crystal electrode and the hybridization between the immobilized probe and the target complementary sequence in solution was monitored. The developed QCM-DNA biosensor represented promising results for a real-time, label-free, direct detection of DNA samples for the screening of genetically modified organisms.     

Enhancement of the efficiency of dye-sensitized solar cell with multi-wall carbon nanotubes/polythiophene composite counter electrodes prepared by electrodeposition

For the purpose of increasing the energy conversion efficiency of dye-sensitized solar cells (DSSCs), multi-wall carbon nanotube (MWCNT)/polythiophene (PTh) composite film counter electrode has been fabricated by electrophoresis and cyclic voltammetry (CV) in sequence. The morphology and chemical structure have been characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), and Raman spectroscopy respectively. The overall energy conversion efficiency of the DSSC employing the MWCNT/PTh composite film has reached 4.72%, which is close to that of the DSSC with a platinum (Pt) counter electrode (5.68%). Compared with a standard DSSC with MWCNT counter electrode whose efficiency is 2.68%, the energy conversion efficiency has been increased by 76.12% for the DSSC with MWCNT/PTh counter electrode. These results indicate that the composite film with high conductivity, high active surface area, and good catalytic properties for I₃⁻ reduction can potentially be used as the counter electrode in a high-performance DSSC.     

拉曼光谱研究聚噻吩微米/纳米管

分别具有 2 0 0nm和 2 0nm管径的聚噻吩微米 /纳米管通过用微孔氧化铝过滤膜作为模板在三氟化硼乙醚溶液中电解聚合噻吩制得。在一张厚度约为 2 0nm的金箔上这些具有单分散长度的微米管能很好平行站立起来形成阵列 ,而纳米管则相互粘附不能形成很好的阵列。用 6 3 3nm激发的拉曼光谱研究表明 :微米管具有较高的掺杂程度 ,而纳米管的掺杂程度很低。这主要是由于两种管子的壁厚不同引起的     

支链带有富勒烯的聚噻吩和齐聚噻吩及其光伏电池研究进展

可溶性聚噻吩和富勒烯(主要是C60)及其衍生物,是聚合物太阳能电池中被广泛使用的给体和受体材料,它们之间的相容性和富勒烯的聚集效应对于太阳能电池能量转换效率有很大影响。将富勒烯与聚噻吩通过共价键连接在一起,可解决它们的共混膜中的相分离问题,有望提高器件效率,是未来有机和聚合物光伏材料研究的一个重要方向。本文按主链是聚噻吩或齐聚噻吩将这种连有富勒烯的材料分为两类,介绍了这些材料的合成方法、电化学性质及基于这些材料的太阳能电池器件近几年来的研究进展。     

Electrochemical Synthesis of Polythiophene in an Ionic Liquid

Polythiophene(PTh) was prepared by the direct electrochemical synthesis in an ionic liquid ([BMIM]PF6) containing 0.1mol/L thiophene by cyclic voltammetry,constant potential and constant current techniques. It is found that smooth and blue-green PTh films can be obtained at a potential of ca. 1.75V(vs. Ag/AgCl) or a current of ca. 1.5mA cm^-2 in the ionic liquid.