Metal nanorods: A new solution for classic problems

ADVANCED NANOMATERIALS AND ITS APPLICATIONS(8-9th August,2008)
School of Materials Science & Nanotechnology,Jadavpur University

Metal nanorods: A new solution for classic problems
Pushan Ayyub
Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005

Metallic nanorods or nanowires are likely to find a variety of exciting applications in nanoelectronic devices as well as in more conventional applications such as gas sensors and solar cells. While there are a number of techniques that give rise to a random collection of nanorods or wires, it is more challenging, and often more useful, to be able to synthesize a parallel array of nanrods anchored to a susbtrate. We have succeeded in producing perfectly aligned metal nanorods with uniform diameter through electrochemical growth within porous anodic alumina templates [1]. Now, an array of isolated metal nanowires is expected to be hydrophilic. We show, however, that a clustering of such nanowires brought about by controlled drying produces a “dual-scale roughness” and confers a strongly hydrophobic property to the surface [2]. The mean size of the nanowire clusters as well as the contact angle are both found to be related to the wire length, and the critical wire length above which the surface becomes hydrophobic is ≈ 10μm. Surface roughness is generally known to enhance water-repellant properties, but this is the first report of roughness-induced hydrophobicity on a bare (uncoated) metallic surface.
We have utilized a metal nanorod array to solve another long standing problem applied electrodynamics: the reduction of the breakdown voltage for electrical discharge under ambient conditions.
REFERENCE:
1. S Gohil, R Chandra, B. Chalke, S Bose and P Ayyub: J. Nanoscience Nanotech. 7 (2007) 641
2. P Bhattacharya, S. Gohil, J. Mazher, S. Ghosh and P. Ayyub, Nanotechnology 19 (2008) 075709

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