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Naoki Toshima - One of the best experts on this subject based on the ideXlab platform.
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thermoelectric properties of polyaniline films with different doping concentrations of 10 Camphorsulfonic Acid
Journal of Electronic Materials, 2013Co-Authors: Hiroaki Anno, Masahiro Hokazono, Fumio Akagi, Makoto Hojo, Naoki ToshimaAbstract:The temperature dependence of the thermoelectric properties was investigated for polyaniline (PANI) films doped with different concentrations of (±)-10-Camphorsulfonic Acid (CSA) with molar ratio x of CSA to two phenyl-nitrogen units of x = 1 to 0.2. All PANI-CSA films exhibit p-type conduction. The temperature dependence of the electrical conductivity of the films with low CSA concentrations is consistent with a transport mechanism of variable-range hopping. On the other hand, the Seebeck coefficient above room temperature shows a linear increase with temperature, attributed to the metallic nature of PANI-CSA. As the CSA concentration decreases, the absolute value of the Seebeck coefficient increases while the electrical conductivity extremely decreases, probably due to the changes not only in the carrier concentration but also in the degree of structural disorder. The power factor increases monotonically with increasing CSA concentration toward x = 1 (the maximum limit). The thermal conductivity value of CSA-PANI film with x = 1 is as low as about 0.20 W m−1 K−1 in the through-plane direction and about 0.67 W m−1 K−1 in the in-plane direction. The thermoelectric figure of merit ZT in the in-plane direction is estimated to be approximately 1 × 10−3 for x = 1.
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Thermoelectric Properties of Polyaniline Films with Different Doping Concentrations of (±)-10-Camphorsulfonic Acid
Journal of Electronic Materials, 2012Co-Authors: Hiroaki Anno, Masahiro Hokazono, Fumio Akagi, Makoto Hojo, Naoki ToshimaAbstract:The temperature dependence of the thermoelectric properties was investigated for polyaniline (PANI) films doped with different concentrations of (±)-10-Camphorsulfonic Acid (CSA) with molar ratio x of CSA to two phenyl-nitrogen units of x = 1 to 0.2. All PANI-CSA films exhibit p-type conduction. The temperature dependence of the electrical conductivity of the films with low CSA concentrations is consistent with a transport mechanism of variable-range hopping. On the other hand, the Seebeck coefficient above room temperature shows a linear increase with temperature, attributed to the metallic nature of PANI-CSA. As the CSA concentration decreases, the absolute value of the Seebeck coefficient increases while the electrical conductivity extremely decreases, probably due to the changes not only in the carrier concentration but also in the degree of structural disorder. The power factor increases monotonically with increasing CSA concentration toward x = 1 (the maximum limit). The thermal conductivity value of CSA-PANI film with x = 1 is as low as about 0.20 W m−1 K−1 in the through-plane direction and about 0.67 W m−1 K−1 in the in-plane direction. The thermoelectric figure of merit ZT in the in-plane direction is estimated to be approximately 1 × 10−3 for x = 1.
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Stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid : Anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.
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stretched polyaniline films doped by 10 Camphorsulfonic Acid anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.
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thermoelectric properties of alternatively layered films of polyaniline and 10 Camphorsulfonic Acid doped polyaniline
Chemistry Letters, 1999Co-Authors: Hu Yan, Naoki ToshimaAbstract:Thermoelectric performance of polyaniline can be improved by formation of multilayered film structure. The alternatively layered films are composed of electrically insulating emeraldine base layers and electrically conducting (±)-10-Camphorsulfonic Acid (CSA)-doped emeraldine salt layers. The multilayered film exhibited 3.5 times higher thermoelectric power factor at ca. 300 K than a bulk film of polyaniline doped by CSA.
Hu Yan - One of the best experts on this subject based on the ideXlab platform.
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Stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid : Anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.
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stretched polyaniline films doped by 10 Camphorsulfonic Acid anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.
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thermoelectric properties of alternatively layered films of polyaniline and 10 Camphorsulfonic Acid doped polyaniline
Chemistry Letters, 1999Co-Authors: Hu Yan, Naoki ToshimaAbstract:Thermoelectric performance of polyaniline can be improved by formation of multilayered film structure. The alternatively layered films are composed of electrically insulating emeraldine base layers and electrically conducting (±)-10-Camphorsulfonic Acid (CSA)-doped emeraldine salt layers. The multilayered film exhibited 3.5 times higher thermoelectric power factor at ca. 300 K than a bulk film of polyaniline doped by CSA.
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Thermoelectric Properties of Alternatively Layered Films of Polyaniline and (.+-.)-10-Camphorsulfonic Acid-Doped Polyaniline.
Chemistry Letters, 1999Co-Authors: Hu Yan, Naoki ToshimaAbstract:Thermoelectric performance of polyaniline can be improved by formation of multilayered film structure. The alternatively layered films are composed of electrically insulating emeraldine base layers and electrically conducting (±)-10-Camphorsulfonic Acid (CSA)-doped emeraldine salt layers. The multilayered film exhibited 3.5 times higher thermoelectric power factor at ca. 300 K than a bulk film of polyaniline doped by CSA.
Gordon G. Wallace - One of the best experts on this subject based on the ideXlab platform.
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influence of electrochemical polymerization temperature on the chiroptical properties of Camphorsulfonic Acid doped polyaniline
Macromolecules, 2006Co-Authors: Yingpit Pornputtkul, Leon A P Kanemaguire, Gordon G. WallaceAbstract:The chiroptical properties of electrochemically deposited emeraldine salt PAn·(+)-HCSA (HCSA = 10-Camphorsulfonic Acid) films have been found to vary markedly with the temperature employed during polymerization. The circular dichroism spectra of such films grown at >40 °C are inverted compared to the spectra of analogous films deposited at temperatures ≤25 °C, indicating an inversion of conformation for the polyaniline chains. These observations are rationalized in terms of a temperature-induced interconversion between the two diastereomeric emeraldine salt products from the doping of the growing polyaniline chains by the chiral (+)-CSA- anion. The marked temperature dependence of the diastereoselectivity highlights the importance of employing a fixed temperature during the electrosynthesis of optically active polyanilines.
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Influence of electrochemical polymerization temperature on the chiroptical properties of (+)-Camphorsulfonic Acid-doped polyaniline
Macromolecules, 2006Co-Authors: Yingpit Pornputtkul, Leon A. P. Kane-maguire, Gordon G. WallaceAbstract:The chiroptical properties of electrochemically deposited emeraldine salt PAn·(+)-HCSA (HCSA = 10-Camphorsulfonic Acid) films have been found to vary markedly with the temperature employed during polymerization. The circular dichroism spectra of such films grown at >40 °C are inverted compared to the spectra of analogous films deposited at temperatures ≤25 °C, indicating an inversion of conformation for the polyaniline chains. These observations are rationalized in terms of a temperature-induced interconversion between the two diastereomeric emeraldine salt products from the doping of the growing polyaniline chains by the chiral (+)-CSA- anion. The marked temperature dependence of the diastereoselectivity highlights the importance of employing a fixed temperature during the electrosynthesis of optically active polyanilines.
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Novel Secondary Dopants for Camphorsulfonic Acid Doped Polyaniline Emeraldine Salts
Australian Journal of Chemistry, 2002Co-Authors: Ian D. Norris, Leon A. P. Kane-maguire, Gordon G. Wallace, Liming Dai, Fan Zhang, Albert W. H. MauAbstract:The doping of emeraldine base with (±)-10-Camphorsulfonic Acid (HCSA) or (+)-HCSA in molten thymol (60°C) or liquid carvacrol (5-isopropyl-2-methylphenol) as solvents provides emeraldine polyaniline (PAn)·HCSA salts (1) with 'expanded coil'-type conformations for their polyaniline chains. Conversion of both racemic PAn·(±)-HCSA (1a) and optically active PAn·(+)-HCSA (1b) films from a 'compact coil' into a partial 'expanded coil' conformation is also facilitated by exposure of the films to either thymol or carvacrol vapours. These conformational changes are supported by modifications to their ultraviolet-visible-near-infrared and circular dichroism spectra and by the marked increase in the electrical conductivity of the films. In the case of carvacrol vapour, treated films of (1a) and (1b) exhibited conductivities of ≥ 130 S/cm, similar to conductivities previously generated by m-cresol. In view of the much lower toxicity of carvacrol compared with m-cresol, it would appear to have considerable promise as an effective 'secondary dopant' for emeraldine salts leading to materials with enhanced electrical conductivity.
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electrochemical formation of chiral polyaniline colloids codoped with or 10 Camphorsulfonic Acid and polystyrene sulfonate
Macromolecules, 1998Co-Authors: Peter C Innis, Ian D. Norris, Leon A P Kanemaguire, Gordon G. WallaceAbstract:Chiral polyaniline colloids have been generated via the electrohydrodynamic polymerization of aniline in aqueous (+)- or (−)-10-Camphorsulfonic Acid (HCSA) using polystyrene sulfonate (PSS) as a steric stabilizer and codopant. Potentiostatic polymerization at +0.9 V (vs Ag/AgCl) was employed. The colloidal PAn·HCSA/PSS dispersions produced after various electropolymerization periods (30−90 min) became optically active upon aging over 24 h, revealing mirror-imaged circular dichroism (CD) spectra for PAn·(+)-HCSA/PSS and PAn·(−)-HCSA/PSS samples. This indicated an enantioselective rearrangement of the polyaniline chains induced by the chiral HCSA dopants after the initial electropolymerization and Acid doping. Dialyzed colloidal dispersions were stable for extended periods (6 months) and revealed particles with a mean size of 180 ± 10 nm, although particles were observed at up to 1000 nm. Similar particles were observed by TEM studies. Chemical dedoping with ammonia of films cast from these dispersions yiel...
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Electrochemical Formation of Chiral Polyaniline Colloids Codoped with (+)- or (−)-10-Camphorsulfonic Acid and Polystyrene Sulfonate
Macromolecules, 1998Co-Authors: Peter C Innis, Leon A. P. Kane-maguire, Ian D. Norris, Gordon G. WallaceAbstract:Chiral polyaniline colloids have been generated via the electrohydrodynamic polymerization of aniline in aqueous (+)- or (−)-10-Camphorsulfonic Acid (HCSA) using polystyrene sulfonate (PSS) as a steric stabilizer and codopant. Potentiostatic polymerization at +0.9 V (vs Ag/AgCl) was employed. The colloidal PAn·HCSA/PSS dispersions produced after various electropolymerization periods (30−90 min) became optically active upon aging over 24 h, revealing mirror-imaged circular dichroism (CD) spectra for PAn·(+)-HCSA/PSS and PAn·(−)-HCSA/PSS samples. This indicated an enantioselective rearrangement of the polyaniline chains induced by the chiral HCSA dopants after the initial electropolymerization and Acid doping. Dialyzed colloidal dispersions were stable for extended periods (6 months) and revealed particles with a mean size of 180 ± 10 nm, although particles were observed at up to 1000 nm. Similar particles were observed by TEM studies. Chemical dedoping with ammonia of films cast from these dispersions yiel...
Hidemoto Kurokawa - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Transformation of (RS)‐1,2,3,4‐Tetrahydro‐3‐ isoquinolinecarboxylic Acid via Salt Formation with (1S)‐10‐ Camphorsulfonic Acid.
ChemInform, 2010Co-Authors: Tadashi Shiraiwa, Tsuyoshi Furukawa, Tamotsu Tsuchida, S. Sakata, Michio Sunami, Hidemoto KurokawaAbstract:Asymmetric transformation of (RS)-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic Acid [(RS)-TIC] by use of (1S)-10-Camphorsulfonic Acid [(S)-CS] as a resolving agent gave a salt of (S)-TIC with (S)-CS with 90% optical purity in hexanoic Acid. The TIC obtained from the salt was purified to give optically pure (S)-TIC in 80% yield based on the starting (RS)-TIC.
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Asymmetric Transformation of (RS)-1,2,3,4-Tetrahydro-3-isoquinolinecarboxylic Acid via Salt Formation with (1S)-10-Camphorsulfonic Acid
Bulletin of the Chemical Society of Japan, 1991Co-Authors: Tadashi Shiraiwa, Tsuyoshi Furukawa, Tamotsu Tsuchida, S. Sakata, Michio Sunami, Hidemoto KurokawaAbstract:Asymmetric transformation of (RS)-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic Acid [(RS)-TIC] by use of (1S)-10-Camphorsulfonic Acid [(S)-CS] as a resolving agent gave a salt of (S)-TIC with (S)-CS with 90% optical purity in hexanoic Acid. The TIC obtained from the salt was purified to give optically pure (S)-TIC in 80% yield based on the starting (RS)-TIC.
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Asymmetric transformation of (RS)-2-phenylglycine via formation of salt with (1S)-10-Camphorsulfonic Acid
Bulletin of the Chemical Society of Japan, 1991Co-Authors: Tadashi Shiraiwa, S. Sakata, Keiko Fujishima, Hidemoto KurokawaAbstract:An asymmetric transformation of (RS)-2-phenylglycine [(RS)-Phg] was carried out via formation of a salt with (1S)-10-Camphorsulfonic Acid [(S)-CS] in acetic Acid, propanoic Acid, or butanoic Acid by heating at 100 °C without using any catalysts such as aldehydes. The rate of epimerization of a more soluble salt of (S)-Phg with (S)-CS was estimated to be lowest in acetic Acid and highest in butanoic Acid. The asymmetric transformation in propanoic Acid, however, was achieved successfully to give the salt of (R)-Phg with (S)-CS with 100% optical purity in 82% yield. Optically pure (R)-Phg was obtained from the salt in 80% yield based on the (RS)-Phg used as the starting material.
Tsukasa Ohta - One of the best experts on this subject based on the ideXlab platform.
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Stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid : Anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.
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stretched polyaniline films doped by 10 Camphorsulfonic Acid anisotropy and improvement of thermoelectric properties
Macromolecular Materials and Engineering, 2001Co-Authors: Hu Yan, Tsukasa Ohta, Naoki ToshimaAbstract:The stretched polyaniline films doped by (±)-10-Camphorsulfonic Acid exhibited significant anisotropy of the electrical and thermoelectric properties. The thermoelectric figure-of-merit (ZT) of the stretched films in the direction parallel to the stretching direction is much higher than that of the unstretched counterpart, and moreover, the ZT increased with increasing drawing ratio. According to the experimental results of X-ray diffraction and UV-Vis-near IR spectroscopy the improvement of the ZT by the stretching process is revealed to be attributable to the increment of carrier mobility, which is proposed to be induced by the extended coil-like conformation of polyaniline.