巯基—聚吡咯薄膜修饰电极的制备及其电化学性能

通过将巯基乙酸作为一种支持电解质,将巯基固定在导电聚吡咯薄膜电极上,从而制得巯基—聚吡咯薄膜修饰电极,该修饰电极保持了巯基的螯合性能,并具有良好的稳定性。对水溶液中的重金属离子具有很好的吸附作用,其灵敏度与未修饰的玻碳电极相比,测汞离子时电沉积提高了3倍,化学吸附时提高了近5倍。并对其吸附机理进行了初步的探讨,证明了其对汞离子的吸附为不可逆的产物弱吸附。     

Surface morphology of polypyrrole core/polyacrolein shell latex by atomic force microscopy (AFM)

 Polypyrrole latex (P(P)), synthesized in Redox polymerization of pyrrole, was used as seed for radical polymerization of acrolein initiated with K₂S₂O₈. In this process the polypyrrole core/polyacrolein shell latex (P(P–A)) was obtained. Morphology of the surface of P(P–A) particles was investigated by atomic force microscopy (AFM). It was found that macromolecules of polyacrolein are not randomly distributed on the surface of polypyrrole but form patches. Apparently, attraction between macromolecules of poly-acrolein in the surface layer is high and the enthalpy of formation of polyacrolein macromolecule clusters is sufficient to compensate, at least, the negative entropy change due to ordering of these macromolecules. Thickness of the polyacrolein layer on the surface of polypyrrole particles, which were covered only partially with polyacrolein, was equal to only 1.6 nm (standard deviation σ= 0.2 nm) and thus, it was reasonable to assume that it corresponded to the monolayer coverage. Received: 30 April 1997 Accepted: 25 August 1997     

聚苯胺和聚吡咯膜电极对Fe（Ⅱ）和Sb（Ⅲ）电催化作用

Ｆｅ（Ⅱ）和Ｓｂ（Ⅲ）的氧化还原峰电流在聚苯胺（ＰＡｎ）和聚吡啶（ＰＰｙ）膜电极上比在铂丝电极上高出一倍至数倍。在膜电极上氧化峰电位与还原峰电位之差值（△Ｅｐ）也比在铂丝电极上显著减小．说明两种膜电极对Ｆｅ（Ⅱ）和Ｓｂ（Ⅲ）离子的电极反应有较好的电催化活性。在电位扫描速度较低时，两种离子在聚合物膜电极上的氧化和还原反应的催化活性相近。     

Polypyrrole/Fe3O4/CNT as a recyclable and highly efficient catalyst for one‐pot three‐component synthesis of pyran derivatives

Polypyrrole (PPY)/Fe₃O₄/CNT has been synthesized and characterized by FT‐IR, TEM and SEM techniques and its catalytic activity has been evaluated in the synthesis of several series of pyran derivatives. Tetrahydrobenzo[b]pyranes, 4H‐pyran‐3‐carboxylates, 4H,5H‐pyrano[3,2‐c]chromenes and dihydropyrano[2,3‐c]pyrazoles have been successfully prepared from one‐pot three‐component condensation of aldehyde, malononitrile and active methylene‐containing compounds (dimedone /ethyl acetoacetate/4‐hydroxycoumarin/3‐methyl‐2‐pyrazoline‐5‐one) using PPY/Fe₃O₄/CNT as a new and reusable heterogeneous catalyst. The present method offer several advantages such as; high yields of products, short reaction times, easy work‐up procedure and easy separation of the catalyst from the reaction mixture due to its magnetic character. Furthermore, chemoselective synthesis of bis‐benzo[b]pyran from terephthalaldehyde can be achieved by this method.     

新型铼系聚吡咯络合物（PPREC）结构与吸附小分子行为的研究

应用ＣＮＤＯ／２研究了铼系聚吡咯络全物的结构及吸附小分子的行为，探究了吸附过程的微观机制。优化了各个体系的几何构型，得到了稳定性与相对于能量、结合能、吸附取向、分子间距的依存关系。     

Intrinsically conducting polymers for electromagnetic interference shielding

This paper summarizes and reviews the research on electromagnetic interference (EMI) shielding with intrinsically conducting polymers (ICPs), mainly polyaniline (PANI) and polypyrrole (PPY), and their composites in various frequency ranges. ICPs are new alternative candidates for EMI shielding applications due to their lightweight, corrosion resistance, ease of processing, and tunable conductivities as compared with typical metals. More importantly, the dominant shielding characteristic of absorption other than that of reflection for metals render ICPs more promising materials in applications requiring not only high EMI shielding effectiveness but also shielding by absorption, such as in stealth technology. Copyright © 2005 John Wiley & Sons, Ltd.     

Low-frequency and temperature-dependent dielectric spectroscopy investigations on polypyrrole nanoparticles

Polypyrrole (PPy) nanoparticles have been synthesized by chemical oxidation method in the presence of anionic surfactant (sodium dodecyl sulphate). The prepared nanoparticles have a diameter of ~28 nm. The low-frequency and temperature-dependent dielectric properties of these nanoparticles have been studied in the temperature range of 77–350 K. Due to absence of the saturated loss peaks, modulus approach has been used for the further insight on the dielectric properties of prepared nanoparticles. The behaviour of the dielectric modulus suggests the Debye-type behaviour of the prepared nanoparticles, where the measured ac conductivity follows the classical hopping conduction mechanism.     

Photoactive Nanostructures of Polypyrrole

The creation of nanostructures of the photoactive polymer polypyrrole (PPy) on glass substrates with the spin‐coating method is described. No additional post‐production treatment is necessary to obtain uniformly distributed photoactive nanostructures on macroscopically scaled substrates. Based on X‐ray reflectivity measurements, the critical solution concentration of PPy below which these nanostructures develop is determined. The PPy nanostructures are displayed with atomic force microscopy (AFM) measurements, which prove that the nanostructures form directly on the substrate. With UV/Vis spectroscopy the absorption behavior of the nanostructures is probed in comparison to PPy films and PPy solutions. A linear dependence of the absorption of the nanostructure on the surface coverage measured with AFM is detected. The influence of confinement on the conjugation length results in a modified absorption behavior of the nanostructures.     

Synthesis and Characterization of Polypyrrole Nanoparticles and Their Nanocomposites with Poly(propylene)

Summary: Conducting polypyrrole (PPy) nanoparticles were synthesized via microemulsion polymerization. PP/PPy nanocomposites were prepared by melt-mixing of polypyrrole with polypropylene (PP) and processed with injection molding. Tensile tests have revealed that increasing amount of PPy increased the strength and the stiffness of the nanocomposite while limiting the elongation of PP. Thermal gravimetric analysis has showed that incorporation of PPy nanoparticles has improved the thermal stability of the nanocomposites. Increasing amount of PPy nanoparticles increases the conductivity of nonconductive PP up to 2,4.10⁻⁴ Scm⁻¹. The same techniques were used to characterize nanocomposites containing 2% w dispersant. Composites prepared with dispersant have involved smaller dimension PPy nanoparticles and exhibited improvement in some mechanical and thermal properties.     

Synthesis of Ag/Polypyrrole Core-Shell Nanospheres by a Seeding Method

Ag/polypyrrole (PPy) core‐shell nanospheres were fabricated through the redox reaction between pyrrole monomer and silver nitrate in the presence of polyvinylpyrrolidone (PVP) and by using the Ag colloidal nanoparticles acting as the seedings. The prepared nanospheres with a shell thickness of 10–12 nm and a core diameter of 20–40 nm are uniform in size and well dispersed. The morphologies, compositions, and electrochemical activities of Ag/PPy composites were characterized by TEM, XRD, FTIR, TGA and CV. The synthetic route employed here is gentle and can be extended to prepare other conducting polymer/inorganic nanocomposites.