Year: 2014
Type: article
Abstract: The surface of a crystal made of roughly spherical molecules exposes, above its bulk rotational phase transition at T = Tr, a carpet of freely rotating molecules, possibly functioning as "nanobearings" in sliding friction. We explored by extensive molecular dynamics simulations the frictional and adhesion changes experienced by a sliding C60 flake on the surface of the prototype system C60 fullerite. At fixed flake orientation both quantities exhibit only a modest frictional drop of order 20% across the transition. However, adhesion and friction drop by a factor of ∼2 as the flake breaks its perfect angular alignment with the C60 surface lattice suggesting an entropy-driven aligned-misaligned switch during pull-off at Tr. The results can be of relevance for sliding Kr islands, where very little frictional differences were observed at Tr, but also to the sliding of C60-coated tip, where a remarkable factor ∼2 drop has been reported.
Source: Nanoscale
DOI: 10.1039/c4nr04641b
Authors: Andrea Benassi, Andrea Vanossi, Carlo A. Pignedoli, Daniele Passerone, Erio Tosatti
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2038131290