Molecular recognition solvents for electrically conductive polyaniline

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Terhi Vikki
  • Lars-Olof Pietilä
  • Heidi Österholm
  • Lisbeth Ahjopalo
  • Antti Takala
  • Alpo Toivo
  • Kalle Levon
  • Pentti Passiniemi
  • Olli Ikkala

Research units

  • Neste Oy
  • VTT Technical Research Centre of Finland
  • Polytechnic University - Brooklyn

Abstract

Due to its semirigid nature, electrically conductive polyaniline (PANI) has long been regarded as an intractable material, i.e. infusible and poorly soluble in organic compounds. Among the rare exceptions is camphorsulfonic acid (CSA) doped PANI, which exhibits good solubility in m-cresol, whereas for other sulfonic acid dopants (e.g. dodecylbenzenesulfonic acid (DBSA)) the solubility in common solvents is poor. We report exceptionally high solubility of fully DBSA and CSA protonated PANI in a crystalline compound, 1,3-dihydroxybenzene, i.e. resorcinol. Up to 20-30 wt % of PANI(DBSA)0.5 and PANI(CSA)0.5 can be dissolved in resorcinol at 200-220 °C to form particle-free films as observed by optical microscopy. High PANI complex concentrations require high temperatures for dissolution, suggesting UCST behavior with a high critical temperature. Optical microscopy, calorimetry, and X-ray analysis suggest that the solution initially is amorphous. With time, crystallinty develops within the sample, due to partial phase separation of resorcinol while part of it remains miscible. Calculations show that a resorcinol molecule is able to simultaneously form two hydrogen bonds and one phenyl/phenyl interaction with the PANI/ sulfonic acid complex, because of their steric match. The conditions required to achieve such matching interactions, i.e. molecular recognition, are discussed. The concept can be extended to find a large category of novel solvents for electrically conductive PANI to yield soluble and fusible complexes.

Details

Original languageEnglish
Pages (from-to)2945-2953
Number of pages9
JournalMacromolecules
Volume29
Issue number8
Publication statusPublished - 1996
MoE publication typeA1 Journal article-refereed

    Research areas

  • molecular recognition, plasticization, polyaniline

ID: 4687477