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Volume 141, 2009
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Water-mediated ordering of nanoparticles in an electric field

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Interfacial polar molecules feature a strongly anisotropic response to applied electric field, favoring dipole orientations parallel to the interface. In water, in particular, this effect combines with generic orientational preferences induced by spatial asymmetry of water hydrogen bonding under confined geometry, which may give rise to a Janus interface. The two effects manifest themselves in considerable dependence of water polarization on both the field direction relative to the interface and the polarity (sign) of the field. Using molecular simulations, we demonstrate strong field-induced orientational forces acting on apolar surfaces through water mediation. At a field strength comparable to electric fields around a DNA polyion, the torques we predict to act on an adjacent nanoparticle are sufficient to overcome thermal fluctuations. These torques can align a particle with surface as small as 1 nm2. The mechanism can support electrically controlled ordering of suspended nanoparticles as a means of tuning their properties and can find application in electro-nanomechanical devices.

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Publication details

The article was received on 29 May 2008, accepted on 19 Jun 2008 and first published on 30 Sep 2008

Article type: Paper
DOI: 10.1039/B809135H
Faraday Discuss., 2009,141, 55-66

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    Water-mediated ordering of nanoparticles in an electric field

    D. Bratko, C. D. Daub and A. Luzar, Faraday Discuss., 2009, 141, 55
    DOI: 10.1039/B809135H

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