Almaky MM

Hassanien R

Horrocks BR

Houlton A

N-(3-pyrrol-1-yl-propyl)-4,4`-bipyridinium hexafluorophosphate (NPPBH) has beensynthesized and polymerized in the presence of DNA to produce DNA-templatedpolymer nanowires (polyNPPBH/DNA). The pyridine group serves as a ligand forCu(II) and to direct the subsequent electroless deposition of Cu to formCu/polyNPPBH/DNA nanowires. UV-vis absorption spectra of the hybrid materialsshow an absorption peak corresponding to the plasmon resonance of Cu0 particles atabout 550 nm. AFM observations show that the Cu/polyNPPBH/DNA nanowires havea wide range of diameters, 10–30 nm, but individual nanowires exhibit a uniformand continuous morphology. The electrical properties of the wires were examined byscanned conductance microscopy and conductive AFM. The nanowire conductivitywas estimated using the diameter and width of the as-prepared nanowires tocalculate the cross-section area (assumed elliptical). We estimate 0.42 \ub1 0.019 S cm-1for the Cu/polyNPPBH/DNA nanowire conductivity. This is substantially greater thanthe polyNPPBH/DNA conductivity (2.1 \ub1 0.26 x10-2 S cm-1) which indicates that thecurrent pathway is via the copper metallization, however the value is much lowerthan bulk Cu. Although the AFM images show relatively regular metal coverage ofthe polymer/DNA wires, the presence of discontinuities or voids along the length ofthe nanostructure is likely. Such gaps in the metal structure may introducesignificant tunneling barriers and a granular metal model is a more appropriatedescription of the Cu/polyNPPBH/DNA nanowires than a simple metallic nanowire

Preparation and electrical properties of a copper-conductive polymer hybrid nanostructure

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