[About the Foresight Institute]|
[Index of Foresight Conferences]
|[Index of Abstracts]|
Physics Department, North Carolina State University
aComputational Nanotechnology at NAS Systems Division of NASA Ames Research Center/MRJ, Moffett Field, CA 94035-1000
bNEC R&D Group, 34 Miyukigaoka, Tsukuba, Ibaraki 305, Japan
This is an abstract for a poster to be presented at the Fifth Foresight Conference on Molecular Nanotechnology.
In spite of many similarities between the macroscopic prototypes and their nanoscale analogs, "small is different". How different -- can often be studied in atomistic computer simulations. For instance, a contact between two atomically smooth macroscopic cylinders allows almost no torque transmission between them. In contrast, in the nanoscale their surfaces are "rough", and van der Walls attraction becomes an important component. This is an interesting idea - will the gear [1,2] work just by virtue of the van der Waals interactions, without any designed teeth? We will present experimental HRTEM images of two carbon nanotubes forming a "toothless gear". We will assess theoretically the cohesion and torque transmission between them. Both continuum macro-scale estimates and the explicit molecular dynamics simulation will be presented. In simulation the C-C interaction is modeled by Brenner's analytic potential within the graphene layers, and by a standard "6- 12" Lennard-Jones for van der Waals forces between the layer within the same tube, or between the different tubes in contact. The inter-axial distance is relaxed, which corresponds to "natural" normal force between the tubes attracted to each other in this scale (an indication of this attraction is the noticeable tube flattening). We observe acceleration of the tube driven by the rotation of another. Energy transmission is less efficient due to the softness of graphene layers and substantial dissipation in their constant bending (internal friction). Role of the temperature, number of layers and the diameters of the tubes will be discussed.
 J. Han, A. Globus, R. Jaffe, G. Deardorff, Nanotechnology v. 8, 95 (1997).
 D. Srivastava, Nanotechnology, submitted (1997).
Boris I. Yakobson, Physics Department, North Carolina State University, Raleigh, NC 27695, Phone: (919)-515-2426, FAX: (919)-515-7331, E-Mail: firstname.lastname@example.org
| Index of Abstracts | Conference Home Page | Index of Foresight Institute Conferences |
| About the Foresight Institute | Foresight Institute Home Page |
Foresight materials on the Web are ©1986-1997 Foresight Institute. All rights reserved.
Last updated 27August97. The URL of this document is: http://www.foresight.org/Conferences/MNT05/Abstracts/Yak3abst.html
Send requests for information about Foresight Institute activities and membership to email@example.com.
Send comments and questions about material on this web site and reports of errors to firstname.lastname@example.org.