Thermoreversible gels of polyaniline: Viscoelastic and electrical evidence on fusible network structures

T. Vikki, Janne Ruokolainen, Olli Ikkala (Corresponding Author), Pentti Passiniemi, Heikki Isotalo, Mika Torkkeli, Ritva Serimaa

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

We demonstrate thermoreversible gelation of a conductive polymer, i.e., rubber-like melt processible electrically conducting compounds. Combination of viscoelastic and electrical conductivity measurements suggests network formation in the gel state and gel melting at elevated temperatures. The gels have been prepared by dissolving polyaniline in dodecylbenzenesulfonic acid (DBSA) using formic acid as a processing medium which was removed at the end. Importantly, without formic acid, reversible gelation and particle-free materials were not achieved even at the resolution of optical microscopy. For T < Tgel the materials behave elastically in compression experiments, the storage and loss moduli do not depend much on frequency, and the electrical conductivity is primarily electronic, probably due to high chain-to-chain hopping conductivity. For T > Tgel the onset of liquid-like flow is detected using modified ball drop method by dynamic mechanical analysis, the dynamic moduli become strongly frequency dependent, and the electrical conductivity drops orders of magnitude to the value corresponding to the ionic conductivity of DBSA, suggesting that the chains are not in direct contact. The physical cross-links are probably localized mesomorphic domains which allow melting.

Original languageEnglish
Pages (from-to)4064 - 4072
Number of pages9
JournalMacromolecules
Volume30
Issue number14
DOIs
Publication statusPublished - 1997
MoE publication typeA1 Journal article-refereed

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formic acid
Polyaniline
Gels
Formic acid
Gelation
Melting
Acids
Rubber
Dynamic mechanical analysis
Ionic conductivity
Optical microscopy
Polymers
Compaction
Liquids
Processing
Electric Conductivity
polyaniline
Experiments
Temperature
dodecylbenzenesulfonic acid

Cite this

Vikki, T., Ruokolainen, J., Ikkala, O., Passiniemi, P., Isotalo, H., Torkkeli, M., & Serimaa, R. (1997). Thermoreversible gels of polyaniline: Viscoelastic and electrical evidence on fusible network structures. Macromolecules, 30(14), 4064 - 4072. https://doi.org/10.1021/ma9615056
Vikki, T. ; Ruokolainen, Janne ; Ikkala, Olli ; Passiniemi, Pentti ; Isotalo, Heikki ; Torkkeli, Mika ; Serimaa, Ritva. / Thermoreversible gels of polyaniline : Viscoelastic and electrical evidence on fusible network structures. In: Macromolecules. 1997 ; Vol. 30, No. 14. pp. 4064 - 4072.
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abstract = "We demonstrate thermoreversible gelation of a conductive polymer, i.e., rubber-like melt processible electrically conducting compounds. Combination of viscoelastic and electrical conductivity measurements suggests network formation in the gel state and gel melting at elevated temperatures. The gels have been prepared by dissolving polyaniline in dodecylbenzenesulfonic acid (DBSA) using formic acid as a processing medium which was removed at the end. Importantly, without formic acid, reversible gelation and particle-free materials were not achieved even at the resolution of optical microscopy. For T < Tgel the materials behave elastically in compression experiments, the storage and loss moduli do not depend much on frequency, and the electrical conductivity is primarily electronic, probably due to high chain-to-chain hopping conductivity. For T > Tgel the onset of liquid-like flow is detected using modified ball drop method by dynamic mechanical analysis, the dynamic moduli become strongly frequency dependent, and the electrical conductivity drops orders of magnitude to the value corresponding to the ionic conductivity of DBSA, suggesting that the chains are not in direct contact. The physical cross-links are probably localized mesomorphic domains which allow melting.",
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Vikki, T, Ruokolainen, J, Ikkala, O, Passiniemi, P, Isotalo, H, Torkkeli, M & Serimaa, R 1997, 'Thermoreversible gels of polyaniline: Viscoelastic and electrical evidence on fusible network structures', Macromolecules, vol. 30, no. 14, pp. 4064 - 4072. https://doi.org/10.1021/ma9615056

Thermoreversible gels of polyaniline : Viscoelastic and electrical evidence on fusible network structures. / Vikki, T.; Ruokolainen, Janne; Ikkala, Olli (Corresponding Author); Passiniemi, Pentti; Isotalo, Heikki; Torkkeli, Mika; Serimaa, Ritva.

In: Macromolecules, Vol. 30, No. 14, 1997, p. 4064 - 4072.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Thermoreversible gels of polyaniline

T2 - Viscoelastic and electrical evidence on fusible network structures

AU - Vikki, T.

AU - Ruokolainen, Janne

AU - Ikkala, Olli

AU - Passiniemi, Pentti

AU - Isotalo, Heikki

AU - Torkkeli, Mika

AU - Serimaa, Ritva

PY - 1997

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N2 - We demonstrate thermoreversible gelation of a conductive polymer, i.e., rubber-like melt processible electrically conducting compounds. Combination of viscoelastic and electrical conductivity measurements suggests network formation in the gel state and gel melting at elevated temperatures. The gels have been prepared by dissolving polyaniline in dodecylbenzenesulfonic acid (DBSA) using formic acid as a processing medium which was removed at the end. Importantly, without formic acid, reversible gelation and particle-free materials were not achieved even at the resolution of optical microscopy. For T < Tgel the materials behave elastically in compression experiments, the storage and loss moduli do not depend much on frequency, and the electrical conductivity is primarily electronic, probably due to high chain-to-chain hopping conductivity. For T > Tgel the onset of liquid-like flow is detected using modified ball drop method by dynamic mechanical analysis, the dynamic moduli become strongly frequency dependent, and the electrical conductivity drops orders of magnitude to the value corresponding to the ionic conductivity of DBSA, suggesting that the chains are not in direct contact. The physical cross-links are probably localized mesomorphic domains which allow melting.

AB - We demonstrate thermoreversible gelation of a conductive polymer, i.e., rubber-like melt processible electrically conducting compounds. Combination of viscoelastic and electrical conductivity measurements suggests network formation in the gel state and gel melting at elevated temperatures. The gels have been prepared by dissolving polyaniline in dodecylbenzenesulfonic acid (DBSA) using formic acid as a processing medium which was removed at the end. Importantly, without formic acid, reversible gelation and particle-free materials were not achieved even at the resolution of optical microscopy. For T < Tgel the materials behave elastically in compression experiments, the storage and loss moduli do not depend much on frequency, and the electrical conductivity is primarily electronic, probably due to high chain-to-chain hopping conductivity. For T > Tgel the onset of liquid-like flow is detected using modified ball drop method by dynamic mechanical analysis, the dynamic moduli become strongly frequency dependent, and the electrical conductivity drops orders of magnitude to the value corresponding to the ionic conductivity of DBSA, suggesting that the chains are not in direct contact. The physical cross-links are probably localized mesomorphic domains which allow melting.

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Vikki T, Ruokolainen J, Ikkala O, Passiniemi P, Isotalo H, Torkkeli M et al. Thermoreversible gels of polyaniline: Viscoelastic and electrical evidence on fusible network structures. Macromolecules. 1997;30(14):4064 - 4072. https://doi.org/10.1021/ma9615056