导电聚合物单体的光电聚合

苯胺、吡咯和噻吩等是重要的导电聚合物单体.光照可促进低聚物的形成,电化学技术可方便地实现单体的电聚合.目前,有关导电聚合物单体的光电聚合的报导还很少.本文研究征水溶液中、铂金属基底上,苯胺、吡咯和噻吩等单体的光电聚合过程.     

水溶液中噻吩的电化学聚合成膜

本文研究水溶液中噻吩的电化学聚合。高酸度水溶液中噻吩先经历化学低聚反应,低聚合物可在较负的电位阳极氧化成膜。     

硅胶表面3-甲基噻吩分子印迹聚合物的制备及吸附特性研究

采用γ-氨丙基三乙氧基硅烷对硅胶微球表面进行接枝修饰,然后以甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,甲苯为溶剂,3-甲基噻吩为模板分子,在硅胶微球表面聚合,得到3-甲基噻吩的硅胶微球表面分子印迹聚合物,用红外光谱进行结构表征。通过考察模板分子、功能单体、交联剂、溶剂的用量等对吸附容量的影响,得到3-甲基噻吩、甲基丙烯酸、二甲基丙烯酸乙二醇酯、甲苯适宜的摩尔聚合比,以此配比合成了3-甲基噻吩表面印迹聚合物,在模拟汽油中,研究了该聚合物对3-甲基噻吩的吸附动力学、吸附选择性、竞争性及再生性能。结果表明,分子印迹聚合物对3-甲基噻吩具有良好的吸附选择性和再生性能,最大吸附容量可达85mg/g,有望将其用于汽油中噻吩类硫的深度脱除,从而弥补加氢脱硫缺陷。     

聚丁基噻吩的合成及性能

用化学聚合方法合成了聚丁基噻吩导电材料,并研究了不同的聚合条件对聚合物性能的影响。聚丁基噻吩导电材料具有较好的稳定性和加工性,其掺杂态的导电率可达到10s/cm。     

乙撑二氧噻吩在中性水溶液中的电化学聚合及行为研究

本文研究了乙撑二氧噻吩在中性水溶液中的电化学聚合过程以及聚乙撑二氧噻吩膜的电化学行为, 利用光电子能谱和红外光谱等方法对聚合物膜进行了表征, 研究表明在中性水溶液中制成的聚乙撑二氧噻吩膜修饰电极具有较好的电化学行为和稳定性。     

光聚合中的吸光度效应—O-酰基肟酮引发体系

研究了几种O-酰基肟酮在313nm和365nm光照下引发丙烯腈和甲基丙烯酸甲酯光聚合。在低吸光度时,聚合速度对引发剂浓度符合0.5次方指数关系,而在高吸光度时,聚合速度、聚合物分子量都与引发剂浓度无关。引发剂消光系数越大,出现其指数为零的浓度越低。     

聚丁基噻吩的电化学合成及性能研究

丁基噻吩在硝基苯溶液中以六氟磷酸四丁基季铵盐为支持电解质，在恒电流条件下进行电化学氧化聚合，通过电导率的测量及可见──紫外光谱分析，讨论了单体浓度、电解质浓度、电流密度、聚合温度对聚合物膜的导电性能的影响。扫描电镜图表明，随着聚合的进行．膜的表面呈“菜花”状结构。循环伏安图表明聚了基噻吩与聚噻吩具有相近的氧化峰位。     

聚噻吩类导电聚合物及其复合膜修饰电极的制备及其在电分析化学中的应用

聚噻吩类导电聚合物修饰电极在电化学检测某些生物分子方面显示出独特的优势,尤其是聚(3-甲基噻吩)(P3MT)修饰电极,这是因为3-甲基噻吩易于电聚合成膜,得到的导电薄膜电导率高、电催化效果好、稳定性高、耐用、抗污染,而且还具有很好的选择性和灵敏性.     

可溶性聚3-[(二茂铁甲酸乙酯)三乙氧基]氧基噻吩的合成与性质表征

采用化学聚合方法合成了一种含二茂铁电活性基团的新型导电聚噻吩衍生物聚3-[(二茂铁甲酸乙酯)三乙氧基]氧基噻吩, 用1H NMR和红外光谱等方法对其结构进行了表征. 实验结果表明, 该聚合物可溶于三氯甲烷、四氢呋喃和丙酮等有机溶剂, 并且二茂铁在聚合物中依然保持良好的氧化还原活性, 对钠离子具有良好的选择性络合作用.     

锂在共轭双键高分子中的电化学嵌入反应III. 锂嵌入聚噻吩的量子化学计算†

采用Gaussian软件和HF方法, 通过从头计算(ab initio)法选取4-31G基组计算锂离子嵌入聚噻吩过程中结构与结合能的变化关系. 发现噻吩聚合时主要生成三或四聚合物. 聚合物在Li原子(或Li^＋离子)嵌入后, 聚噻吩间距离明显变小, 同时发生电荷转移, 形成稳定嵌合物; 并使噻吩环的C-α—C-β键级变小. 同时, 研究了锂离子(或原子)嵌入后体系的HOMO, LUMO能级. 聚噻吩在嵌入锂离子时LUMO轨道能级变为负值, 成为电池反应得电子的正极. 而金属Li₂ 释放Li^＋后的Li^－的HOMO能级为＋0.7427 eV, 则成为给电子的负极. 由此, 可以完成由锂/聚噻吩在高氯酸锂电解质中组成的放电过程, 并提出嵌合键级概念用来表征锂在聚噻吩间的结合程度.     

The Electrochemical Polymerization of Thiophene in Aqueous Sotations of an Acid

People are more and more interested in polythiophene because of its night stability.At present,organic solvent system is still commonly used in electrochemical polymerization of thiophene and the related electrochemical studies.However,it is more practical to use aqueous solutions instead of organic solvents.The electrochemical polymerization of thiophene in aqueous solution of acid is discussed in this paper.In highly concentrated acidic solution,thiophene first undergoes low polymerization,and then the low polymer can be oxidized at the comparatively negative potential to form film.     

Regioselective grignard metathesis reaction of 2,5‐dibromo‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene and kumada coupling polymerization

2,5‐Dibromo‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene ( DBPyTh ) was synthesized by the Suzuki coupling reaction between two aromatic compounds followed by the bromination. The Grignard metathesis reaction of DBPyTh with isopropylmagnesium chloride proceeded in 85% conversion and the regioselective halogen–metal exchange at the 2‐position was confirmed. Namely, 5‐bromo‐2‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene and 2‐bromo‐5‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene were generated in 90:10 molar ratio. Subsequently, the Kumada coupling polymerization was carried out using 1,3‐bis(diphenylphosphinopropane)nickel(II) dichloride to obtain poly(3‐(6′‐hexylpyridine‐2′‐yl)thiophene) ( PolyPyTh ). The polymer molecular weight could be roughly controlled by the catalyst concentration and the molecular weight distribution ranged from 1.25 to 1.80. The gas chromatograph analysis indicated that 5‐bromo‐2‐chloromagnesio‐3‐(6′‐hexylpyridine‐2′‐yl)thiophene was preferentially polymerized in 90% conversion and the percentage of the head‐to‐tail content (regioregularity) was calculated to be 96%. The matrix‐assisted laser desorption/ionization time‐of‐fright mass spectrum indicated that both polymer chain ends were substituted with the hydrogen atom. The absorption maxima of polymer in CHCl₃ and thin film were observed at 447 and 457 nm, respectively, which were blue‐shifted compared with poly(3‐(4′‐octylphenyl)thiophene). From the CV measurement of the polymer thin film, highest occupied molecular orbital (HOMO) (?5.31 eV) and lowest unoccupied molecular orbital (LUMO) (?3.76 eV) energy levels were calculated from the oxidation and reduction onset potentials, respectively, and the electrochemical band gap energy was determined to be 1.62 eV. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Low potential electropolymerization of thiophene at a copper oxide electrode

Conductive polythiophene (PT) film was electrochemically deposited onto a copper electrode covered with an oxide film from distilled BF₃–diethyl ether (BFEE) solution containing 15 mM thiophene, and the oxidation potential of thiophene was relatively low (1.0 V versus Ag|AgCl). The obtained film was homogenous and flexible, and could be easily cut into any shape as desired.     

Electrochemical doping in electrolyte-gated polymer transistors

By comparing the changes in pi-pi* absorption with the transconductance in PEO-LiClO4 electrolyte-gated FETs, we have demonstrated that the high channel currents obtained at low gate voltages result from reversible electrochemical doping of the semiconducting polymer film. At low temperatures, the conductivity of the electrochemically doped poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene), PBTTT-C14, is nonlinear with a crossover from dsigma(T)/dT > 0 to dsigma(T)/dT approximately 0 as a function of the source-drain voltage. High current densities, up to 10(6) A/cm2 at 4.2 K, can be sustained in the electrochemically doped PBTTT-C14 films.     

Ellipsometric examination of electrically conductive films of poly(2,5-thiophenediyl)

A polymer film formed by anodic oxidation of thiophene in acetonitrile on platinum at 2.08 V was examined by ellipsometry. The refraction index and absorption index were determined as a function of the wavelengths. The optical thickness was determined and compared with the electrical charge. Stoichiometric film growth by a two-electron reaction followed this comparison. The film properties studied were almost independent of the potential between −0.1 and +2.08 V. The time dependence of the ellipsometric parameter showed the film growth to be approximately linear with square root of time, typical for a diffusion controlled reaction.     

Synthesis,solid‐state,and charge‐transport properties of conjugated polythiophene‐S,S‐dioxides

An alkylated semiconducting polymer comprising alternating bithiophene‐[all]‐S,S‐dioxide and aromatic monothiophene units in the polymer backbone was synthesized with the intent of modifying the energy gap and lowest unoccupied molecular orbital for use as a stable n‐type semiconductor. Films spun from this semiconducting polymer were characterized utilizing X‐ray scattering, near edge X‐ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, and thin‐film field effect transistors to determine how oxidation of the thiophene ring systems impacts the structural and electronic properties of the polymer. The thiophene‐S,S‐dioxide polymers have lower optical and electrical band gaps than corresponding thiophene polymers. X‐ray scattering results indicate that the polymers are well ordered with the π–π stacking distances increased by 0.4 Å relative to analogous thiophene polymers. The electrical stability of these polymers is poor in transistors with a drop in the field effect mobility by approximately one order of magnitude upon addition of just 5% of the thiophene‐S,S‐dioxide unit in a copolymer with thiophene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Microstructure evolution and device performance in solution-processed polymeric field-effect transistors: the key role of the first monolayer

Probing the role of the first monolayer in the evolution of the film polymer microstructure is essential for the fundamental understanding of the charge carrier transport in polymeric field-effect transistors (FETs). The monolayer and its subsequent microstructure of a conjugated polymer [poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene), PBTTT] film were fabricated via solution deposition by tuning the dip-coating speed and were then studied as accumulation and transporting layers in FETs. Investigation of the microstructure of the layers prepared at different coating velocities revealed that the monolayer serves as an important base for further development of the film. Significant improvement of the charge carrier transport occurs only at a critical multilayer network density that establishes the required percolation pathways for the charge carriers. Finally, at a low dip-coating speed, the polymer chains are uniaxially oriented, yielding pronounced structural anisotropy and high charge carrier mobilities of 1.3 cm(2) V(-1) s(-1) in the alignment direction.