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  • 11
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Simultaneous chemical copolymerization and oxidation of pyrrole and N-methylpyrrole by iodine has been carried out. The electrical conductivity, the I− 3 content and the amount of positively charged pyrrolylium nitrogen decrease with increasing N-methylpyrrole content in the copolymer complexes.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1435-1536
    Keywords: Key words Fluorescence emission technique ; dynamic light scattering ; intrinsic viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The synthesis, viscometric, and fluorescence properties of a water-soluble zwitterionic sulfobetaine copolymer, poly(ADMMAPS)/NA, are reported. When fluorescent hydrophobes (naphthyl group) are incorporated into the zwitterionic copolymer, the photophysical response may effectively probe solution behavior on the microscopic level. Experimental results indicate that I E/I M steadily increases with increases in polymer concentration. I E/I M in aqueous solution is greater than that in aqueous potassium chloride solution. Dynamic light scattering (QELS) measurements show that hydrodynamic diameters of the naphthalene-labeled zwitterionic sulfobetaine copolymer increase with an increasing salt concentration. Viscosity studies reveal that the polymer coil expanded as more salt is added. In fluorescence quenching study, the reduction in the quenching efficiency of Tl+ with salt addition can arise from enhanced compartmentalization of naphthalene labels as added electrolyte enhances intrapolymer micellization. The intrapolymer micelle is easily formed, indicating that the thallium ion has difficulty reacting with bound naphthalenes located in the polymer coil. The naphthalene-labeled zwitterionic sulfobetaine copolymer is depicted as a compacted polymer coil conformation in deionized water because of intra-and inter-associations. Consequently, salt addition breaks up the associations and enhances the intrapolymer micellization. The microscopic and macroscopic behaviors of zwitterionic sulfobetaine copolymer differ a lot from those of the corresponding cationic copolymer.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 19 (1988), S. 325-331 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Simultaneous chemical oxidation and polymerization of azulene by iodine and bromine were carried out. The polyazulene-bromine complex is electrically conductive and partially soluble in organic solvents whereas the polyazulene-iodine complex is much less conductive and insoluble. The physicochemical properties of the polyazulene-bromine complex were characterized by elemental and thermogravimetric analyses, infrared and ultraviolet-visible absorption spectroscopy, cyclic voltammetry and gel permeation chromatography. Experimental evidences suggest that the soluble fraction of the complex consists mainly of azulene oligomers.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract X-ray photoelectron spectroscopy was employed for the in situ study of interactions between thermally evaporated Mg atoms and electroactive polyaniline (PANI) films of various intrinsic oxidation states. Quantitative changes in the N1s core-level spectra and the Mg2p core-level spectra, as well as the changes in surface chemical stoichiometry of these films throughout the Mg evaporation process were carefully monitored. Although the nitrogen sites appeared to be more attractive to the in-coming Mg atoms and the emeraldine base (EB) and nigraniline base (NA) films underwent an apparent decrease in intrinsic oxidation state ([=N-]/[-NH-] ratio) as a result of Mg evaporation, there is no direct interaction between the two species. On the other hand, the adsorbed oxygen from the bulk of the polymer film played a dominant role in the interfacial interactions between the polymer and the metal. Characterization of the delaminated indium-tin-oxide (ITO) and polymer surfaces from EB film and its camphorsulfonic acid-doped counterpart cast on ITO substrates had also been carried out to evaluate the interaction of PANI with the high work function metal.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Films of electroactive polymers, such as polyaniline (PAN) in its emeraldine base form, and poly(3-alkylthiophene), poly(3-hexylthiophene) (P6TH), poly(3-octylthiophene) (P8TH), and poly(3-dodecylthiophene) (P12TH) can be readily functionalized via thermal or near ultraviolet-light-induced surface graft copolymerization with monomers of polyelectrolyte, polyampholyte and polymeric acids. The monomers used in the present work include dimethyl sulphate quaternized dimethylamino-ethylmethacrylate (DMAEM·C2H6SO4), 3-dimethyl(methacryloyloxyethyl)ammonium propane sulphonate (DMAPS), acrylic acid (AAc) and a sodium salt of styrene sulphonic acid (NaSS). The surface structures and compositions of the electroactive polymer films after functionalization via graft copolymerization were characterized by angle-resolved X-ray photoelectron spectroscopy. Graft copolymerization of poly(3-alkylthiophene) films, but not PAN films, with the hydrophilic monomers readily results in a stratified surface microstructure arising from the migration of the hydrophilic graft chains beneath a thin surface layer which is much richer in the substrate chains. On the other hand, graft copolymerization of PAN films with AAc and NaSS readily gives rise to a self-protonated (and thus conductive) surface structure.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The chemical nature of the nitrogens in polypyrrole (PPY) and poly(N-methylpyrrole) (PMPY) has been critically compared using X-ray photoelectron spectroscopy as a primary tool. Treatment of PPY/perchlorate complex with NaOH results in a deprotonation process which gives rise to a PPY base (DP-PPY) having an intrinsic oxidation state consisting of 25% oxidized imine-like (=N-) structure, similar to that observed in the 50% oxidized emeraldine state of polyaniline. This intrinsic oxidation state, however, does not exist in the nitrogen-substituted PPY. As a result, the charge-transfer (CT) mechanisms involving the two base polymers and the various oxidants and electron acceptors are vastly different. The PMPY base undergoes strong CT interactions with metal oxidants, such as Cu(ClO4)2, but interacts only weakly with organic electron acceptors, such as the halobenzoquinones and cyanobenzoquinones. The reverse is true for DP-PPY. Both polymer complexes also exhibit different thermal degradation behaviour.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 4365-4374 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaniline-tetracyanoethylene (TCNE) complexes can be synthesized either from emeraldine base or emeraldine hydrochloride by a relatively simple method. The complexes demonstrate greater stability than the emeraldine hydrochloride at elevated temperatures and under high current densities. The electrical conductivity of the complexes synthesized from emeraldine base can be varied from 〈 10-6 to 0.2 S/cm by varying the amount of TCNE incorporated. The complexes synthesized from emeraldine hydrochloride are slightly more conductive than the starting emeraldine hydrochloride. In both types of complexes, it appears that electron transfer between the polyaniline and TCNE has occurred resulting in the formation of some positively charged polyaniline nitrogen and TCNE anions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 357-366 
    ISSN: 0887-624X
    Keywords: surface graft copolymerization ; adhesive-free adhesion ; polycarbonate ; XPS ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The surfaces of ozone-pretreated polycarbonate films were subjected to further modification by thermally induced graft copolymerization with acrylic acid (AAc), sodium salt of styrene sulfonic acid (NaSS), N,N-dimethylacrylamide (DMAA), N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-dimethyl(methacryloyl ethyl)-ammonium propanesulfonate (DMAPS) monomers. The structure and composition at the copolymer interface were studied by angle-resolved X-ray photoelectron spectroscopy (XPS). For polycarbonate films with a substantial amount of grafted polymer, the hydrophilic graft penetrates or becomes partially submerged beneath a thin surface layer of dense substrate chains. This microstructure was further supported by the water contact angle measurements. Adhesive-free adhesion studies revealed that the AAc, DMAA or DMAPS graft copolymerized polycarbonate film surface adhered strongly to another similarly modified surface (homo-interface) when brought into direct contact in the presence of water and subsequently dried. The development of the lap shear strength is dependent on the concentration of the surface graft, the microstructure of the grafted surface, the adhesion (drying) time, and the nature of the interfacial interaction. The simultaneous presence of chain entanglement and electrostatic interaction readily results in substantially enhanced adhesion strengths between two DMAPS graft copolymerized surfaces or between an AAc and a DMAA graft copolymerized surface (hetero-interface). XPS analyses of the delaminated surfaces suggest that failure occurred cohesively below the graft-substrate interface. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 357-366, 1998
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 2143-2153 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simultaneous chemical polymerization and oxidation of pyrrole have been initiated by organic electron acceptors, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetrachloro-o-benzoquinone(chloranil). The polypyrrole (PPY) complexes so produced are semiconductive and granular in nature. For the PPY-DDQ and PPY-chloranil complexes obtained from bulk polymerization, the respective electrical conductivities (σ) are of the order of 10-1 and 10-3 ohm-1 cm-1. However, σ is substantially lower for the complexes prepared in solvent media. Both complexes are relatively stable in the atmosphere. Thin uniform films of the PPY-organic acceptor complexes have also been synthesized on SnO2 electrode by electrochemical polymerization in acetonitrile. The physicochemical properties of the PPY-organic acceptor complexes prepared chemically under the various experimental conditions are examined in detail.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 759-766 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The changes in the structure of leucoemeraldine (LM) and emeraldine (EM) base upon doping by perchlorate anions are studied by X-ray photoelectron spectroscopy (XPS) and infrared (IR) absorption spectroscopy. In the case of LM, interactions of the amine nitrogens with the perchlorate anions result in a nitrogenonium ion structure analogous to that arising from the protonation of imine nitrogens in EM by HCl except the chloride anion in the latter has been replaced by the perchlorate anion. A small amount of partially ionic and covalent chlorine is also incorporated in the LM-perchlorate complexes. The maximum electrical conductivity that is achieved in these complexes is about 4 S/cm. In contrast, the maximum conductivity of the EM-perchlorate complexes is three orders of magnitude lower. The interactions of perchlorate anions with EM base result in the preferential disappearance of the imine units over the amine units.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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