Synthesis, manipulation and conductivity of supramolecular polymer nanowires.
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.
Dong
Liqin
L
Chemical Nanoscience Laboratories, School of Natural Sciences, University of Newcastle, Newcastle upon Tyne, NE1 7RU, UK.
Hollis
Tom
T
Fishwick
Steven
S
Connolly
Bernard A
BA
Wright
Nicholas G
NG
Horrocks
Benjamin R
BR
Houlton
Andrew
A
D004247:DNA / Q000737:chemistry; D004553:Electric Conductivity; D046911:Macromolecular Substances / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties
D046911:Macromolecular Substances; D011108:Polymers; D011758:Pyrroles; D012996:Solutions; C067635:polypyrrole; D004247:DNA