COLL 321 |
| M. Curry1, Xiao Li2, Fengting Xu3, Feng Huang4, J. A. Barnard3, Mark Weaver2, and S. C. Street1. (1) Department of Chemistry, The University of Alabama, Box 870336, Tuscaloosa, AL 35487, (2) Department of Metallurgy and Materials Engineering, University of Alabama, Box 870202, AL, (3) Department of Materials Science and Engineering, The University of Pittsburgh, Pittsburgh, PA 15261, (4) Center for Materials for Information Technology, University of Alabama |
| We have observed that the presence of an adsorbed dendrimer monolayer on technological interesting substrates, e.g. dendrimer monolayer adsorbed on Si, dramatically alters the growth modes and nanomechnical properties of deposited Au and Cu films. A substantial increase in the nanomechnical hardness with decreasing grain size has been observed for ultrathin Au dendrimer hybrid nanocomposite films (Au/D/Si) when compared to its counterpart, films of the metal alone (Au/Si), in direct agreement with metal film strengthening according to the Hall-Petch relation. Recent reports by Karsten et al. indicate that for crystals of sufficient size dislocation mediated plasticity dominates film deformation. However, as the size of the crystals decreases below 12 nm a transition in the deformation mechanism to atomic sliding at the grain boundary occurs. Hindering either of these motions is believed to result in Hall-Petch behavior. Our results suggest that grain boundary sliding is hindered in the presence of the dendrimer monolayer (e.g. dendrimer acting as a glue) allowing Hall-Petch type behavior to occur, and restricting lateral deformation of Au and Cu films, improving their wear properties. |
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Friction, Lubrication, and Adhesion in Micro- and Nano-Scale Devices
8:30 AM-12:00 PM, Tuesday, March 30, 2004 Marriott -- Orange County 5, Oral
Division of Colloid and Surface Chemistry |