Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 24). / In this research, the manipulation of colloidal systems composed of superparamagnetic particles in water is studied by a simulation method. In response to an external magnetic field, the dipoles drive the beads to self-assemble into chains, which rotate and consequently move across a nearby surface. Under strong surface-interaction, the dynamic and equilibrium structures are modeled using a Bell model and measured using Monte Carlo-type update steps. It is shown that the walking motion can be characterized as two different regimes corresponding to an increase of the rotating arm from half to all of the chain-length as the activation barrier of binding interaction increases with a constant overall increase in energy. When operating at rotational frequencies from 1 Hz to 9 Hz and applied field from I mT to 9 mT, the corresponding translational velocities of chain-like rotors can be approximated with a two-state model until the fragmentation transition of chain-like rotors takes place. The translational velocities of chain-like rotors scale linearly with respect to number of beads. / by Yi-Han Su. / S.B.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/83780 |
| Date | January 2013 |
| Creators | Su, Yi-Han, S.B. Massachusetts Institute of Technology |
| Contributors | Alfredo Alexander-Katz and Mehran Kardar., Massachusetts Institute of Technology. Department of Physics., Massachusetts Institute of Technology. Department of Physics. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 24 pages, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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