Self-organization of nano-lines and dots triggered by a local mechanical stimulus
- Fabio Biscarini*,†,
- Massimiliano Cavallini*,
- Rajendra Kshirsagar*,
- Giovanni Bottari‡,
- David A. Leigh†,‡,
- Salvador León§, and
- Francesco Zerbetto†,§
- *Istituto per lo Studio dei Materiali Nanostrutturati, Consiglio Nazionale delle Ricerche, Sezione di Bologna, Via P. Gobetti 101, I-40129 Bologna, Italy;
- ‡School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, United Kingdom; and
- §Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via F. Selmi 2, I-40126 Bologna, Italy
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Edited by Jack Halpern, University of Chicago, Chicago, IL, and approved September 19, 2006 (received for review June 21, 2006)
Abstract
When a local mechanical perturbation is applied to the surface of a thin film of a mechanically interlocked molecule (a rotaxane), the molecules self-organize into periodic arrays of discrete dots or lines. The dimensionality of the nanostructures depends on whether the mechanical stimulus acts along a 1D line or over a 2D area. The size (50–500 nm) and periodicity (100–600 nm) of the patterns are controlled solely by the film thickness. This self-organization at the mesoscopic scale occurs via a nucleation-ripening mechanism eased by the relatively low energy barriers of the intramolecular rearrangement introduced by the mechanical bond. The phenomenon can be exploited as a bottom-up nanofabrication method.
Footnotes
- †To whom correspondence may be addressed. E-mail: f.biscarini{at}bo.ismn.cnr.it, david.leigh{at}ed.ac.uk, or francesco.zerbetto{at}unibo.it
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Author contributions: F.B., D.A.L., and F.Z. designed research; and M.C., R.K., G.B., and S.L. performed research.
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The authors declare no conflict of interest.
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This article is a PNAS direct submission.
- Abbreviation:
- AFM,
- atomic force microscope.
- © 2006 by The National Academy of Sciences of the USA
