Synthesis, manipulation and conductivity of supramolecular polymer nanowires

Chemistry. 2007;13(3):822-8. doi: 10.1002/chem.200601320.

Abstract

The synthesis of supramolecular conducting nanowires can be achieved by using DNA and pyrrole. Oxidation of pyrrole in DNA-containing solutions yields a material that contains both the cationic polypyrrole (PPy) and the anionic DNA polymers. Intimate interaction of the two polymer chains in the self-assembled nanowires is indicated by FTIR spectroscopy. AFM imaging shows individual nanowires to be continuous, approximately 5 nm high and conformationally flexible. This feature allows them to be aligned by molecular combing in a similar manner to bare DNA and provides a convenient method for fabricating a simple electrical device by stretching DNA/PPy strands across an electrode gap. Current-voltage measurements confirm that the nanowires are conducting, with values typical for a polypyrrole-based material. In contrast to polymerisation of pyrrole on a DNA template in bulk solution, attempts to form similar wires by polymerisation at surface-immobilised DNA do not give a continuous coverage; instead, a beads-on-a-string appearance is observed suggesting that immobilisation inhibits the assembly process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA / chemistry
  • Electric Conductivity
  • Macromolecular Substances / chemical synthesis*
  • Macromolecular Substances / chemistry
  • Models, Molecular
  • Molecular Structure
  • Nanostructures / chemistry*
  • Oxidation-Reduction
  • Particle Size
  • Polymers / chemical synthesis*
  • Polymers / chemistry
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry
  • Solutions / chemistry
  • Surface Properties

Substances

  • Macromolecular Substances
  • Polymers
  • Pyrroles
  • Solutions
  • polypyrrole
  • DNA