合成单股导电聚合物的方法

T.Bein等发现,在氧化剂存在的条件下,利用三维Y型沸石中的孔洞和一维丝光沸石,可使吸在沸石中的单体(如噻吩、吡咯和苯胺)在孔道中的聚合成为一种单股的导电聚合物。用HF将沸石溶解后可以取出上述产     

从导电聚吡咯到共轭聚合物光伏材料——我在中科院化学所30年共轭高分子研究历程

本文简要回顾了本人在中科院化学所30年的研究历程,重点介绍了在共轭高分子(包括导电聚吡咯电化学、聚合物发光电化学池(LEC)和共轭聚合物给体光伏材料)方面的研究成果。在导电聚吡咯电化学方面,对导电聚吡咯的电化学制备和电化学性质进行了深入研究,阐明了各种电化学聚合条件对制备的导电聚吡咯电导和力学强度等的影响,发现电解液溶剂给电子性(Donor number)对吡咯电化学聚合制备的导电聚吡咯电导的影响:溶剂Donor number越小制备的导电聚吡咯电导越高;使用非离子表面活性剂添加剂在水溶液中制备出表面非常光滑和高力学强度的导电聚吡咯薄膜;对于吡咯电化学聚合提出了电解液阴离子参与的阳离子自由基聚合机理,并推到出吡咯电化学聚合反应的动力学方程;发现在NaNO3水溶液中电化学聚合制备的导电聚吡咯除存在主链氧化、对阴离子掺杂结构外,还存在质子酸掺杂结构;阐明了导电聚吡咯在水溶液中电化学还原和再氧化的机理及其电化学过程的可逆性和稳定性,以及导电聚吡咯在有机电解液中特殊的第一次还原和再氧化的机理。在LEC方面,通过交流阻抗法确认了LEC的电化学掺杂机理和p-i-n结构,合成了多种适用于LEC的主链带离子导电单元的兼具离子导电性的发光嵌段共聚物,避免了LEC活性层中存在的发光聚合物和离子导电聚合物的分相问题;使用离子液体作为电解质制备了室温准冷冻p-i-n结LEC,改善了LEC的电致发光性能。在共轭聚合物给体光伏材料方面,我们提出了通过共轭侧链来拓宽聚合物吸收和提高空穴迁移率的分子设计思想,设计和合成了一系列带共轭侧链的二维共轭聚噻吩衍生物以及基于二噻吩取代苯并二噻吩的窄带隙高效二维共轭聚合物给体光伏材料。我们使用烷硫基取代进一步降低了这类二维共轭聚合物的HOMO能级从而进一步提高了其光伏性能。最后介绍了本组二维共轭聚合物给体光伏材料在非富勒烯聚合物太阳能电池方面的最新研究进展。     

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。     

导电聚合物的电化学制备和电化学性质研究——中国科学院有机固体重点实验室导电聚合物电化学研究工作简介(I)

简要介绍本研究组自上世纪80年代以来在导电聚合物的电化学制备和电化学性质研究中取得的一些主要成果,包括吡咯电化学聚合条件的影响、电化学聚合反应机理及其反应动力学、导电聚吡咯的两种掺杂结构及其两步电化学氧化还原过程和电化学过氧化的机理、导电聚苯胺的电化学性质、导电聚合物稳定性的电化学解释等等.     

导电高分子材料电化学合成过程中的计量化学关系

导电高分子材料可以通过电化学方法合成,在合成过程中,电解液中的阴离子以一定比例作为反离子结合在聚合物 中,然后沉积在电极表面.本文以聚吡咯为例,对此过程进行了计量化学探主坟,导出了生成的聚合重量与反应中消耗的电量及反离子大小和比例间的关系.十二磺酸聚吡咯、扁桃酸聚吡咯、讥氯酸聚吡咯与氯化聚吡咯的电化学合成证实了以上关系.实验与计算表明,氯化聚吡咯中由于反离的分子量接近单体分子量的1/2,故生成的聚合物重量与反离子在聚合筘的比例无关.     

聚噻吩的合成方法

自从1977年白川英树等发现聚乙炔这种导电聚合物以来,打破了高分子材料长期以来被认为是绝缘体的观点。随后聚苯胺、聚吡咯、聚噻吩等的出现使导电聚合物的种类不断出新,其用途也扩展到如导电材料、电极材料、催化材料以及太阳能电池等应用中,且已有部分产品实现了商品化。其中,聚噻吩因其良好的稳定性、易于制备、掺杂后具有良好的光电化学性能等特点而受到广泛关注。本文总结了几种合成聚噻吩及其衍生物的常见方法,包括化学氧化聚合法、电化学聚合法、金属催化偶联法、光致合成法、光电化学沉积法,以及近年来新发现的固相聚合法和酸催化聚合法,并简要介绍了各自的合成机理及优缺点。     

聚吡咯并[3,4-c]吡咯的电子结构及导电性研究

采用密度泛函(DFT)方法在6-31g(d)水平下研究了聚吡咯和聚吡咯并[3,4-c]吡咯, 以及它们的单体和低聚物的电子结构. 对中心键的键长、电荷密度以及Weberg键级的研究表明, 随着主链聚合度的增加, 其共轭性增强. 对聚合物还进行了能带结构和态密度分析. 结果发现, 在3位聚合的并环化合物具有最优的导电性能, 其能隙仅有0.25 eV, 可以作为潜在的导电聚合物材料.     

导电聚合物的电化学制备和电化学性质研究--中国科学院有机固体重点实验室导电聚合物电化学研究工作简介(Ⅰ)

简要介绍本研究组自上世纪80年代以来在导电聚合物的电化学制备和电化学性质研究中取得的一些主要成果,包括吡咯电化学聚合条件的影响、电化学聚合反应机理及其反应动力学、导电聚吡咯的两种掺杂结构及其两步电化学氧化还原过程和电化学过氧化的机理、导电聚苯胺的电化学性质、导电聚合物稳定性的电化学解释等等．     

聚噻吩的光电化学研究

导电聚合物是由一些具有共轭π键的聚合物经化学或电化学掺杂后形成的导电率可从绝缘体延伸到导体范围的一类高分子材料。其中噻吩及其衍生物具有导电率高、环境稳定性好、成膜性好、禁带宽度小等特点,是用做光伏电池的理想材料。相继报道的有聚3-甲噻吩[1]、聚3-己基噻吩[2],聚(3-十一烷基-2,2’-并噻吩)[3]等。对于聚噻吩的光电化学性质的研究,在国际上很少见报道,国内尚未见报道,本文对聚噻吩(PTh)的光电化学性质进行了研究。1实验部分1.1仪器与试剂光电化学实验采用带石英窗口的三电极电解池,工作电极为ITO/PTh膜电极,参比电极为饱和…     

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。     

Kinetics of film formation by interfacial polycondensation

An approximate analytical model of film formation by interfacial polycondensation is presented. The analysis requires knowledge of a minimal set of certain kinetic parameters (monomer diffusivities and reaction rate constants) and reaction conditions (monomer concentrations and thickness of the unstirred layer). The process proceeds as a succession of two or three markedly different kinetic regimes. Each regime (insipient film formation, slowdown, and diffusion-limited growth) sets a different pattern of local polymer accumulation, with important implications for the structure of the emerging film. At the incipient stage, a loose polymer film begins to emerge in a fixed narrow region inside the boundary layer, followed by gradual densification of the middle part of the film. A condition for film formation is thus formulated on the basis of our analysis. The model predicts that two different scenarios are possible, which depend on the permeability of the polymer: films with a low permeability to both monomers pass through an abrupt slowdown of film growth, whereas permeable films undergo a smooth transition between the incipient film formation and diffusion-limited regimes. The model incorporates the highly important effects of the accumulation of reactive end groups and the decrease of monomer diffusion with the polymer concentration on the kinetics of the process and film characteristics. In addition, the validity of the utilized mean-field approach is analyzed, and the analysis suggests a direct correlation between the roughness and the thickness of the film. The results are in good agreement with an earlier numerical study and the direct structural studies of polyamide membrane films.     

In situ study of electrocopolymerization of acrylamide,formaldehyde, and N,N′-methylenebisacrylamide

An apparatus and procedure for real-time in situ investigations of monomer electropolymerization in solution using optical microscopy with differential interference and phase contrast have been designed. The kinetics of electropolymerization of an acrylamide-formaldehyde monomer mixture in aqueous solution has been studied. An induction period of electropolymerization was fixed and evaluated for the first time. Growth of the polymer film after disconnection has been visualized. The dynamics of this phenomenon is evaluated, and possible reasons are discussed. Anisotropic mechanical stresses, arising in the polymer film during electropolymerization, have been found and characterized. The mechanism that is responsible for the formation of a dense near-cathode layer has been revealed. The formation of a zinc sublayer during electropolymerization has been examined. Reasons for the roughness of the near-electrode surface of the polymer film and for high adhesion of the electrodeposited polymer film to the metal have been established.     

Electropolymerization : direct film formation on metal substrates-I: Kinetics and mechanism

Attempts have been made to produce, in situ, polymer films on tinplate cathodes by the electrolysis of conducting solutions of vinyl monomers for use in the can-lacquering industry. Study of a range of vinyl monomers revealed that film formation occurs at low monomer conversion only in the electrolysis of acrylonitrile and methacrylonitrile in NN'-dimethyl formamide. The highest rates of film formation were obtained by constant current electrolysis when tetraethyl ammonium p-toluene sulphonate (McKee Salt) was used as electrolyte. The rate of film formation increases with monomer concentration to a maximum and then falls rapidly. Chain propagation occurs by an anionic mechanism with ion pair formation favoured at high monomer concentrations. The physical properties of the coloured films produced rarely approach those required industrially and the method does not represent an alternative approach to the lacquering of food and beverage cans.     

A multiswitchable poly(terthiophene) bearing a spiropyran functionality: understanding photo- and electrochemical control

An electroactive nitrospiropyran-substituted polyterthiophene, poly(2-(3,3'-dimethylindoline-6'-nitrobenzospiropyranyl)ethyl 4,4'-didecyloxy-2,2':5',2'-terthiophene-3'-acetate), has been synthesized for the first time. The spiropyran, incorporated into the polymer backbone by covalent attachment to the alkoxyterthiophene monomer units, leads to multiple colored states as a result of both photochemical and electrochemical isomerization of the spiropyran moiety to merocyanine forms as well as electrochemical oxidation of the polyterthiophene backbone and the merocyanine substituents. While electrochemical polymerization of the terthiophene monomer can take place without oxidation of the spiropyran, increasing the oxidation potential leads to complex electrochemistry that clearly involves this substituent. To understand this complex behavior, the first detailed electrochemical study of the oxidation of the precursor spiropyran, 1-(2-hydroxyethyl)-3,3-dimethylindoline-6'-nitrobenzospiropyran, was undertaken, showing that, in solution, an irreversible electrochemical oxidation of the spiropyran occurs leading to reversible redox behavior of at least two merocyanine isomers. With these insights, an extensive electrochemical and spectroelectrochemical study of the nitrospiropyran-substituted polyterthiophene films reveals an initial irreversible electrochemical oxidative ring-opening of the spiropyran to oxidized merocyanine. Subsequent reduction and cyclic voltammetry of the resulting nitromerocyanine-substituted polyterthiophene film gives rise to the formation of both merocyanine π-dimers or oligomers and π-radical cation dimers, between polymer chains. Although merocyanine formation is not electrochemically reversible, the spiropyran can be photochemically regenerated, through irradiation with visible light. Subsequent electrochemical oxidation of the nitrospiropyran-substituted polymer reduces the efficiency of the spiropyran to merocyanine isomerization, providing electrochemical control over the polymer properties. SEM and AFM images support the conclusion that the bulky spiropyran substituent is electrochemically isomerized to the planar merocyanine moiety, affording a smoother polymer film. The conductivity of the freestanding polymer film was found to be 0.4 S cm(-1).     

聚{N-[2-(4′-硫代乙酸苄酯基)丙酰基]-对氨基苯乙炔}的合成和热稳定性及有序纳米结构的形成

采用两性离子型的催化剂Rh+[η-C6H5(nbd)B-(C6H5)3]实现了含手征性中心和硫代乙酸酯基的苯乙炔单体的聚合,用红外光谱、核磁共振氢谱和紫外-可见吸收光谱表征了聚合物的结构,证实得到了预期产物.聚合物的重均分子量达到了73200,在氯仿、四氢呋喃、二氯甲烷等有机溶剂中有良好的溶解性能.聚合物热稳定性高,在氮气氛围下热分解温度为336℃,在900℃的高温下有31%的重量残留.用扫描电子显微镜观察发现,在浓度为5.0mg/mL的聚合物氯仿溶液形成的薄膜中有微米长度的棒状有序结构;由浓度为0.5mg/mL的聚合物氯仿稀溶液形成的薄膜表面有晶体析出.用透射电子显微镜观察聚合物在氯仿溶液中缓慢形成的微结构,发现当浓度高于1.0mg/mL时,聚合物在碳膜上形成铺展的薄膜,薄膜由纳米尺寸的丝带状结构取向排列而成;当浓度低于0.5mg/mL时,聚合物形成具有规则几何形态的微晶体.在聚合物热稳定性的显著提高和有序微结构的形成过程中,聚苯乙炔侧链中的手征性中心发挥了关键的作用.     

Kinetics and mechanism of oxidation of fumarate,acrylate, cinnamate,and maleate anions by hexavalent manganese in aqueous alkaline medium

Kinetics of oxidation of fumarate, acrylate, cinnamate, and maleate anions by hexavalent manganese has been studied in aqueous alkaline medium. The order in [oxidant] was unity while that in [substrate] was fractional. The order of reactivity of anions is fumarate → acrylate → cinnamate → maleate. The reactions followed Michaelis–Menten kinetics suggesting the formation of a cyclic intermediate between Mn(VI) and the substrate followed by its disproportionation in a slow step. The equilibrium constant (K) for the preequilibrium step and the rate constant (k) for the slow disproportionation step have been calculated from the intercept and the slope values of the linear plot of 1/k_obs versus 1/[substrate]. Activation parameters are also presented and discussed. A convenient iodometric method is reported for the estimation of Mn(VI).     

噻吩光电化学聚合的研究

噻吩在水溶液中先经低聚反应,生成的低聚合物再在阳极氧化成膜,光照可促进低聚合物的形成,使噻吩在Pt、Au基低上选择性地进行光电聚合。即在低于噻吩电聚合电位下,形成明显光照点的聚噻吩膜。     

Initiated chemical vapor deposition of trivinyltrimethylcyclotrisiloxane for biomaterial coatings

Organosilicon polymers show great utility as both biocompatible and electrically insulating materials. In this work, thin films of a novel organosilicon polymer are synthesized by initiated chemical vapor deposition utilizing trivinyltrimethylcyclotrisiloxane as a monomer and tert-butyl peroxide as a free-radical-generating initiator. Use of an initiator allows for the formation of polymer films at filament temperatures as low as 250 degrees C, significantly lower than those required to thermally polymerize the monomer species. The mild reaction conditions allow for the retention of all siloxane ring moieties within the resulting polymer. Films deposited at filament temperatures of 600 degrees C or higher exhibit damage to this moiety. The all-dry deposition process generates a highly cross-linked matrix material in which over 95% of the vinyl moieties present on the monomer units have been reacted out to form linear polymerized hydrocarbon chains. While each hydrocarbon backbone chain averages 8.9 monomer units in length, as evaluated by X-ray photoelectron spectroscopy analysis, each monomer unit is involved in three independent chains, resulting in polymer films of such high molecular weight that they are completely insoluble. Kinetic analysis of the deposition process indicates that the film formation rate is limited by the adsorption of reactive species to the deposition substrate, with an apparent activation energy of -23.2 kJ/mol with respect to the substrate temperature. These results are consistent with a surface growth mechanism, ideal for the coating of nonuniform or high aspect ratio substrates.     

Solid-state polymerization of long-chain vinyl compounds. I. Effect of molecular arrangement on polymerizability of octadecyl methacrylate

γ-Ray-initiated postpolymerization of octadecyl methacrylate in polymorphic crystals and melt has been investigated to clarify the effect of molecular arrangement of the monomer on polymerizability. From thermal, x-ray, and infrared (IR) analyses this long-chain monomer exhibited three crystalline modifications that we refer to as α-, sub-α, and β-forms. The β-form (mp 28.7–29.7°C), which is obtainable from solution, is a stable state with triclinic chain packing. The α-form (mp 19.5–20.0°C), which is obtained first from the melt but transforms into β-form on storing, is a metastable state with hexagonal chain packing. The sub-α-form appears transiently in α→β transition. The polymerizability of octadecyl methacrylate in the β-form is extremely low, whereas the α-form can polymerize easily and the initial polymerization rate, saturated conversion, and polymer molecular weights increase with temperature. Polymerizability in the molten state at fairly high temperature is rather low, however. Thus maximum polymerizability is obtained just above the melting point of α-form. It has been found that particular orientation and suitable packing mode with some freedom of rotational motion of the monomer molecules in layered structure accelerate the polymerization reaction.     

Electrochemical synthesis of a polypyrrole thin film with supercritical carbon dioxide as a solvent

A conductive polypyrrole (PPy) film was successfully synthesized in a homogeneous supercritical carbon dioxide (scCO2)/acetonitrile (AN) system. The occurrence of a homogeneous supercritical state was confirmed by observations of the phase behavior of the system through a high-pressure cell with a viewing window. The concentration of a supporting electrolyte, tetrabutylammonium hexafluorophosphate (TBAPF6), significantly changed the phase behavior of the scCO2/AN system. The polymerization rate of the film in that system decreased with further addition of CO2. This result suggested that the low viscosity of scCO2 did not play an important role in improving the growth rate of the PPy film. The low polymerization rate might have been due to the electron-transfer resistance arising from the low dielectric constant of scCO2/AN mixture. The roughness of the film prepared in the homogeneous scCO2/AN system was 1/10 that synthesized in AN itself as a solvent. The slow growth of film and the high diffusion rate of the monomer seemed to account for the smooth flat film formation.