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  • Chemistry  (11)
  • *Economic Development
  • Cell & Developmental Biology
  • 1990-1994  (11)
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  • 1
    Electronic Resource
    Electronic Resource
    A comparative study on the structural changes in leucoemeraldine and emeraldine base upon doping by perchlorate (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 759-766 
    Details
    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to that arising from the protonation of imine nitrogens in EM by HCl except the chloride anion in the latter has been replaced by the perchlorate anion.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
    URL: http://dx.doi.org/10.1002/pola.1991.080290518
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  • 2
    Electronic Resource
    Electronic Resource
    Charge transfer interactions in some poly[[o-(trimethylsilyl)phenyl] acetylene]-acceptor complexes (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 669-676 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Charge transfer (CT) interactions between poly[[o-(trimethylsilyl)phenyl]acetylene] or poly(o-Me3SiPA) and some electron acceptors were studied by ultraviolet-visible and infrared absorption spectroscopy and by x-ray photoelectron spectroscopy, (XPS). The electron acceptors used included iodine, bromine, o-chloranil, o-bromanil, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), and tetracyanoethylene (TCNE). Varying degrees of CT interactions were observed in all of the polymer/acceptor complexes studied. The electrical conductivities σ of the organic acceptor complexes exhibited a strong acceptor concentration dependence at low acceptor levels, with the DDQ complex exhibiting the highest σ. The extent of CT and the redistribution of charges resulting from the CT in all the complexes were revealed by XPS. The poly (o-Me3SiPA)/I2 complex film lost iodine spontaneously while more than half of the bromine in the poly (o-Me3SiPA)/Br2 complex existed as covalently bonded bromine, even at low halogen loading.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1991.090290604
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  • 3
    Electronic Resource
    Electronic Resource
    Protonation of leucoemeraldine in the solid state and in solution (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 395-401 
    Details
    ISSN: 0887-6266
    Keywords: leucoemeraldine, protonation of ; x-ray photoelectron spectroscopy study of protonation of leucoemeraldine ; polyanilines, spectroscopic studies of protonation of ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The protonation of leucoemeraldine in power form and in N-methylpyrrolidinone (NMP) solution by HCIO4 and HBF4 has been studied by x-ray photoelectron spectroscopy (XPS), infrared (IR), and ultraviolet (UV)-visible absorption spectroscopy. In powder form, less than 25% of the amine nitrogens can be protonated in the absence of oxygen. The effects of oxygen on the degree of protonation and the distribution of amine and imine units upon deprotonation of the salt are investigated. The degree of protonation in leuccemeraldine can be increased to about 50% with 3 M HCIO4, similar to that achievable with emeraldine base in powder form. In NMP solution, leucoemeraldine is easily oxidized by dissolved oxygen. Protonation of both leucoemeraldine and emeraldine base in NMP solutions results in metastable species which gradually undergo deprotonation. The resulting products are affected by the O2 content of the solutions. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090310403
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  • 4
    Electronic Resource
    Electronic Resource
    Electroless reduction and precipitation of gold from acid solution by polypyrrole (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 53 (1994), S. 1539-1545 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The oxidation of the 25% intrinsically oxidized polypyrrole, containing 25% [=N-] and 75% [—NH—], and the subsequent reprotonation and reduction of the highly intrinsically oxidized polymer in acid gold solution were utilized for the spontaneous and sustained reduction of gold. The X-ray photoelectron spectroscopic (XPS) results indicate that only elemental gold [or Au (0)] accumulates on the polymer film or powder surfaces. The N1s core-level spectra of the protonated and deprotonated polypyrrole after metal reduction suggest that the intrinsic structure of the polymer at the polymer/Au interface remains intact, even at [Au]/[N] mol ratios substantially above 1. The process, however, is limited by the decreasing effective surface area of the polymer due to Au coverage. The Au reduction behavior of polypyrrole was also compared to that of polyaniline. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070531116
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  • 5
    Electronic Resource
    Electronic Resource
    X-ray photoelectron spectroscopic studies of charge transfer interactions in electroactive polyaniline (1994)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 5 (1994), S. 171-177 
    Details
    ISSN: 1042-7147
    Keywords: Polyaniline ; XPS ; Charge transfer ; Oxidation states ; Films ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Four modes of charge transfer interactions in polyaniline (PAN), viz. acid protonation, self-doping, charge transfer interactions with organic acceptors, and charge transfer interactions with surface grafted functional polymers have been studied by X-ray photoelectron spectroscopy (XPS). In the case of acid protonation, the protonation behavior of volatile and non-volatile acid differs. The structures of sulfonated leucomeraldine (LM) and nigraniline (NA) are similar to those of sulfonated and self-protonated emeraldine (EM). A substantially higher degree of charge transfer interaction with the organic acceptors is observed for EM film that has been subjected to one cycle of acid/base treatment. The charge transfer interactions with the organic acceptors have proceeded further than the pure formation of molecular complexes. Both pristine and Ar plasma or O3 pretreated EM films are susceptible to surface modifications by graft copolymerization. The protonic acid functional groups of the graft readily give rise to a self-protonated EM surface.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1994.220050305
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  • 6
    Electronic Resource
    Electronic Resource
    Surface structures of fluoropolymer, polyolefin and polyester films after modification by graft polymerization (1994)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 5 (1994), S. 837-842 
    Details
    ISSN: 1042-7147
    Keywords: Polyolefin ; Fluoropolymer ; Polyester ; Graft Polymerization ; Surface structure ; XPS ; SIMS ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Pristine and argon plasma pretreated polytetrafluoroethylene (PTFE), polystyrene (PS), high-density polyethylene (HDPE) and poly(ethylene terrephthalate) (PET) films have been subjected to near-UV light-induced graft polymerization with water-soluble acrylamide (AAm), the sodium salt of styrene sulfonic acid (NaSS), acrylic acid (AAc) and N,N-dimethylaminoethylmethylacrylate (DMAEMA) monomers. The structure and composition at the substrate surface with grafted polymer were studied by angle-resolved X-ray photoelectron spectroscopy (XPS). In most cases, the density of surface grafting is enhanced by plasma pretreatment. For each polymer substrate with a substantial amount of grafting, the hydrophilic graft penetrates or becomes partially submerged beneath a thin surface layer of dense substrate chains. This stratified microstructure is consistent with the static secondary ion mass spectroscopy (SIMS) and Ar+ beam depth profiling results. The two latter techniques also suggest that when the grafted polymer has a bulky substituent, there is less efficient penetration of the grafted polymer below the surface.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1994.220051211
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  • 7
    Electronic Resource
    Electronic Resource
    Thermal degradation studies of perchlorate-doped conductive polymers (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 573-579 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermogravimetric behavior of polypyrrole (PPY), polybithiophene (PBT), and poly-aniline (PAN) perchlorate complexes and their corresponding base polymers have been studied. The PBT-perchlorate complex and base polymer decompose at significantly lower temperatures than do the PPY and PAN counterparts. All three perchlorate complexes retain half or more of their original conductivities with no changes in the doping levels after one cycle of heating to 150°C in air and cooling to room temperature. However, after heating at 150°C for 24 h, only the PAN-perchlorate complex shows no significant change in the doping level, although its conductivity decreases by more than two orders of magnitude. X-ray photoelectron spectroscopy analyses of the perchlorate complexes reveal the presence of at least two distinct chlorine species. The thermal decomposition of the perchlorate anions results in the formation of volatile chlorine species as well in chlorine covalently bonded to the polymer. The thermal decomposition of the PPY-perchlorate complex also results in the conversion of positively charged nitrogens to iminelike structures.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070430319
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  • 8
    Electronic Resource
    Electronic Resource
    A calculation method for analysis of SIMS spectra from oxidation of metals in H2 16O/H2 18O/16O2 gas mixtures (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 20 (1993), S. 645-650 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A calculation method for the secondary ion mass spectrometry (SIMS) analysis of the reaction of a pure metal with gas mixtures of water and oxygen is introduced. Equation systems are to be solved, each expressed as: Y = A × X, where Y is an amplitude column measured from the SIMS spectrum, A is a matrix constructed from the relative abundances of isotopes of the metal and X is an unknown amplitude column of the relevant species MeaOHb±(a = 1, 2; b = 0, 1, 2 and 3). The applicability of the calculation method has been tested in SIMS analysis of ex situ-grown iron oxides with different and known 18O contents. In in situ oxidation, measurement of the ratio of H216O/H218O in the metal-water-oxygen reaction allows fractions of O in the species MeaOHb+ that originate from water to be calculated. Data from such calculations have been used to study the initial stage of the reaction of Fe and Cr in H216O/H218O/16O2 gas mixtures. The results are interpreted in terms of coupled/uncoupled reaction type, reactivity of metal to water relative to oxygen in the mixed gas and degree of dissociation of water.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740200806
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  • 9
    Electronic Resource
    Electronic Resource
    Polyaniline with high intrinsic oxidation state (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 20 (1993), S. 833-840 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Polyaniline (PAN) samples of high intrinsic oxidation states, such as the nigraniline (NA) and pernigraniline (PNA) oxidation states, were prepared by chemical oxidation of the 50% oxidized emeraldine (EM) base and the fully reduced leucoemeraldine (LM) base, according to the methods reported in the recent literature. X-ray photoelectron spectroscopy (XPS) was used as a primary tool for the quantitative analysis of the benzenoid amine, quinonoid imine and positively charged nitrogens corresponding to any particular intrinsic oxidation state and protonation level of the polymer. The use of iodine and ammonium persulfate as oxidants can lead to structural alterations, such as halogen addition in the former and over-oxidation and degradation in the latter. Less structural changes are observed in the m-chloroperoxybenzoic acid-oxidized material. In all the cases studied, XPS results indicate that only the 75%-oxidized NA base has been obtained in the dry state. The fully oxidized PNA probably exists in the m-chloroperoxybenzoic acid-oxidized material before drying, as suggested by optical absorption spectroscopy. The charge transfer interactions of the NA powders and films with dopants in aqueous and non-aqueous media were also investigated briefly.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740201006
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  • 10
    Electronic Resource
    Electronic Resource
    The intrinsic redox states in polypyrrole and polyaniline: A comparative study by XPS (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 19 (1992), S. 33-37 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: X-ray photoelectron spectroscopy provides a useful tool for the critical comparison of the chemical nature of the nitrogens corresponding to the various intrinsic redox states of electroactive polypyrrole (PPY) and polyaniline (PAN) and their N-substituted derivatives. Proton modifications of the PPY nitrogens can give rise to a number of intrinsic redox states corresponding to various proportions of the imine-like (=N—) and amine-like (—NH) nitrogens, similar to those observed in PAN. For complexes prepared from oxidative polymerizations, the intrinsic oxidation level of PAN is always about twice that of PPY (50% vs. 25%). The behaviours of the nitrogens of the corresponding redox states in both polymers towards oxidation, reduction, protonation and charge transfer interactions are grossly similar. However, the amine nitrogens in the emeraldine (EM) oxidation state of PAN (50% =N— structure) are more susceptible to protonation in the presence of excess protonic acids than those of the 25% deprotonated PPY (DP-PPY). Finally, the doping level in poly(N-methylaniline) (PMAN) is twice that of poly(N-methylpyrrole) (PMPY). The base polymers of PMAN and PMPY exist only in the fully reduced state and are susceptible to reoxidation. The nitrogens of PMAN, but not PMPY, are also susceptible to protonation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740190110
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