Polymerized aniline in porous amorphous frameworks: A vibrational and conductivity study

Colomban, Philippe; Efremova, Anastasiia; Régis, A.; Vendange, V.; Grüger, A.; Badot, Jean-Claude

doi:10.1016/0927-6513(94)00085-a

Cited by 11 publications

(8 citation statements)

References 26 publications

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“…The glass transition temperature ( T g ) of long-chained polyaniline is close to 420 K, , but much lower values are expected for short-chain polymers and, furthermore, for the tetramer. A huge dynamic disorder is thus expected at 300 K. Furthermore, two families of polymorphs, the EBI/ESI and EBII/ESII forms, have been recognized. ,,, High-resolution electron microscopy has clearly revealed that amorphous and “crystalline” zones are not located randomly: crystalline regions are located in the center of rolled sheets or clews. In contrast, the matter at the periphery is amorphous .…”

Section: Resultsmentioning

confidence: 99%

“…A huge heterogeneity of the electromagnetic properties results from the different regions/islands composing the materials. This affects the IR absorption analysis of polyaniline salt dispersed, in KBr or ICs pellets, or paraffin oil: well-defined transmission windows arise from reflections at the interface between conducting and nonconducting regions, perturbing the absorption curve of the conductive materials. For this reason, only the IR spectra of BB, BBB, and EB samples could be obtained from reflectance measurements (Figure , Table ).…”

Section: Resultsmentioning

confidence: 99%

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Nature of Protons, Phase Transitions, and Dynamic Disorder in Poly- and Oligoaniline Bases and Salts: An Inelastic Neutron Scattering Study

Khalki¹,

Colomban²,

Hennion

2002

Macromolecules

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An inelastic neutron scattering study of polyaniline (camphorsulfonic and chloride salts, emeraldine base in the form of powder or film) from ca. 1 to 120 cm-1 shows significant changes in the compounds as a function of the temperature. Intensity and bandwidth undergo major modifications below 50 K, because of the freezing of the dynamic ring disorder. The greatest modifications were observed for camphorsulfonic acid salt. In the range from 100 to 3000 cm-1, a nonlocalized inelastic scattering process previously assigned to the “free protons” (in other words, noncovalently bonded hydrogen atoms) was also observed. Comparison with the spectra of oxidized tetramer (BQBBa), BB (diphenylamine), BBB (N,N‘-diphenyl-1,4-phenylenediamine), and BQB (-diimine) model compounds shows that, at the neutron spectrometer resolution, the dynamics of BQB already give a good basis for the aromatic ring dynamics in a polyaniline framework. Assignment of the modes is proposed in the light of low-wavenumber Raman and IR spectra. The thermal disordering of the rotational degrees of freedom appears very similar to that observed in crystalline benzene.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Nature of Protons, Phase Transitions, and Dynamic Disorder in Poly- and Oligoaniline Bases and Salts: An Inelastic Neutron Scattering Study

Khalki¹,

Colomban²,

Hennion

2002

Macromolecules

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“…X-ray diffraction clearly evidences that different degrees of organization are present. − In the “crystalline part”, a strong interchain Coulombian coupling is expected through the ordered anions while in the “amorphous part”, despite the large chain disorder, a significant interchain coupling should remain as evidenced by the high mechanical strength of a film − and crystalline regions ,, has failed to date. In fact, the correlation length and “crystallinity” highly depend on the synthesis of the pristine materials and its following history.…”

Section: Resultsmentioning

confidence: 99%

Vibrational Study of Short-Range Order and Structure of Polyaniline Bases and Salts

1999

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Raman and infrared reflection spectra in the backbone deformations and lattice modes range (10−1000 cm-1) of EB/ES-I and EB/ES-II polyanilines are discussed and compared with those of an oligomer (BQBBa) and of the constitutive bricks of the polyaniline skeleton: diphenylamine (BB), N,N‘-diphenyl-1,4-phenylenediamine (BBB), and N,N‘-diphenyl-1,4-phenylenediimine (BQB). Short-range structure, scaling motif, and disorder are discussed. Emphasis is given to the relationship between hybridization, short-range structure, disorder, and optical properties. Ring, CH deformations, and librational/translational modes appear very sensitive to the static and dynamic disorder. Results show that vibrational spectroscopy allows to distinguish the two classes of polyaniline (ES-I and ES-II), whatever the inserted anion. The sketch of a continuous change of angle between the rigid virtual N−ring−N bond is proposed to describe the static orientational disorder.

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“…In these systems, the transition metal ion associate to the inorganic structure plays a role of oxidizing agent that promotes the aniline polymerization. Raman and FTIR spectroscopies were employed to characterize the polymer formed by the oxidative polymerization of aniline using Cu(II) in HFe(SO 4 ) 2 ·4H 2 O and HUO 2 PO 4 ·4H 2 O layered compounds, and also in mesoporous aluminosilicate gels. , In accordance with these studies, an oligomeric mixture was produced, having segments formed due to the head-to-tail coupling and also due to a head-to-head polymerization, responsible for the presence of hydrazo bonds (N−N).…”

Section: Introductionmentioning

confidence: 90%

Spectroscopic Characterization of Polyaniline Formed by Using Copper(II) in Homogeneous and MCM-41 Molecular Sieve Media

2005

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This work emphasizes the important role of the synthetic parameters in the structure of the polymeric material obtained in the aniline polymerization. The polymers formed by the oxidative polymerization of aniline by copper(II) ions in acidic aqueous solution, acetonitrile/water medium, and also copper(II) acetate complex encapsulated into MCM-41 molecular sieve were characterized by resonance Raman spectroscopy using three exciting laser lines and other techniques such as UV−vis, FTIR, and XANES (Nitrogen K edge). Additionally the products were investigated by thermogravimetric analysis and powder X-ray diffraction. When Cu(II) ions in acidic aqueous medium are used, emeraldine salt (ES−PANI) is formed through the usual head-to-tail polymerization mechanism, while in acetonitrile/water medium a polymer is observed having mainly phenazine-like rings, quinonediimine, and/or phenylenediamine segments in the chains, suggesting that a distinct mechanism is operating. The average molecular weights of the free polymers synthesized in water and in acetronile/water were, respectively, ca. 37 300 and 16 900 Da. The encapsulated polymer synthesized in Cu(II)-MCM-41 is a polymeric mixture of (i) ES−PANI and (ii) the polymer obtained when this metal cation was used as oxidant in acetonitrile/water medium. All the characterization data were compared to those ones obtained for standard free polyaniline and also for the encapsulated polymer into mesoporous MCM-41 formed by using persulfate in acidic aqueous medium as oxidant.

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Polymerized aniline in porous amorphous frameworks: A vibrational and conductivity study

Cited by 11 publications

References 26 publications

Nature of Protons, Phase Transitions, and Dynamic Disorder in Poly- and Oligoaniline Bases and Salts: An Inelastic Neutron Scattering Study

Nature of Protons, Phase Transitions, and Dynamic Disorder in Poly- and Oligoaniline Bases and Salts: An Inelastic Neutron Scattering Study

Vibrational Study of Short-Range Order and Structure of Polyaniline Bases and Salts

Spectroscopic Characterization of Polyaniline Formed by Using Copper(II) in Homogeneous and MCM-41 Molecular Sieve Media

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