Browsing by Author "GODOY, A"

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    CHANGE WITH TIME OF THE PROPERTIES OF POLY(SELENO-P-NAPHTHALENE DIAMINE) DOPED WITH CHLORINE
    (ELSEVIER SCI LTD, 1995) BERNEDE, JC; SAFOULA, G; MOLINIE, P; GODOY, A; MHARZI, H; CONAN, A; DIAZ, F; TREGOUET, Y
    After synthesis, poly(seleno-p-arylene diamine) has been doped with chlorine. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) have been carried out on the doped powder. The changes in the experimental results with storage time have been systematically analyzed. It is observed that, relative to carbon, the atomic percentage of oxygen increases with time while the signals of N, Cl and Se decrease. The changes in the N1s and Se3d spectra show that the polymer is progressively decomposed by chlorine. This decomposition is in good agreement with the change in the ESR signal. These modifications can explain the decrease in conductivity with increasing storage time.
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    CHEMICO PHYSICAL CHARACTERIZATION OF QUINIZARIN THIN-FILMS DEPOSITED BY EVAPORATION
    (1993) BENNASRALLAH, T; BERNEDE, JC; GODOY, A; RABILLER, C; LEGOFF, D
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    CHEMICOPHYSICAL CHARACTERIZATION OF THE POLY(TETRAHALO-P-PHENYLENESELENIDE)S SEMICONDUCTING POLYMERS
    (1993) GODOY, A; BERNEDE, JC
    Chemico-physical characterization of semiconducting polymers having selenium in the chain have been done by XPS, microprobe analysis and optical absorption. The binding energy of Se3d peak shows that there are positive partial charges on the selenium atoms. The high chemical shift of the C1s binding energy in the case of C-Br is attributed to the s-character of bromine when bound to carbon. This s-character gives an effective electronegativity higher than Pauling's value. After doping, the binding energy of the dopant (Cl or I) corresponds to the anion position. Therefore we can imagine that during doping there is polaron or bipolaron formation. The hypothesis of polaron formation is conforted by optical absorption experimental results. The homogeneity of the powder has been checked by microprobe analysis. The relative concentrations are nearly the one expected.
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    EVOLUTION WITH TIME OF PROPERTIES OF THE POLYTETRABROMO-P-PHENYLENEDISELENIDE DOPED WITH AN HALOGEN (CL OR I)
    (EDITIONS SCIENTIFIQUES ELSEVIER, 1994) BERNEDE, JC; GODOY, A; MOLINIE, P; SAFOULA, G; MHARZI, H; DIAZ, F; CONAN, A
    PBrPDSe has been doped by chlorine or iodine. The samples have been studied by X ray photoelectron spectroscopy (XPS), electron spin resonance (E.S.R.) and with a scanning electron microscope equiped with an electronic microprobe. Conductivity measurements have also been performed on pressed pellet samples.
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    POLY(TETRAHALO-P-PHENYLENESELENIDE)S - NEW SEMICONDUCTING POLYMERS
    (1989) DIAZ, FR; TAGLE, LH; GARGALLO, L; RADIC, D; GODOY, A
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    SYNTHESES, CHARACTERIZATION AND ELECTRICAL-PROPERTIES OF SEVERAL POLY(SELENO-P-ARYLENEDIAMINES)
    (1995) DIAZ, FR; TAGLE, LH; GODOY, A; CONTRERAS, S
    Polymers derived from aromatic diamines and containing selenium between the two nitrogen atoms were synthesized and characterized. The electrical conductivities were measured before and after doping with I-2, SbF5, AlCl3 and FeCl3, showing semiconducting properties when doped with I-2 and SbF5.
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    THERMAL-STABILITY OF POLY(MONO-N-ALKYL-ITACONATES) AND MONO-N-ALKYLITACONATE-CO-VINYLPYRROLIDONE COPOLYMERS .1.
    (1994) RADIC, D; TAGLE, LH; OPAZO, A; GODOY, A; GARGALLO, L
    Poly(monoitaconates) containing octyl, decyl and dodecyl groups and random monoalkylitaconate-co-vinylpyrrolidone copolymers were studied by thermogravimetric analysis. Copolymers of mono-n-octylitaconate (MOI), mono-n-decylitaconate (MDI), and mono-n-dodecylitaconate (MDoI), respectively, with N-vinyl-2-pyrrolidone (VP) of different compositions were studied by dynamic thermogravimetric analysis. The thermal stability of the copolymers depends on the structure of the monoitaconate comonomer and on the composition of the copolymer. The kinetic analysis of the degradation data shows that the thermal decomposition of these copolymers can be described by several kinetic orders depending on the copolymer and on the composition. The relative thermal stability of the copolymers increases as the VP content increases and as the length of the side chain of the itaconate increases, following the same trend as the flexibility of the copolymers in solution.