Polymer-mediated entropic forces between scale-free objects
The number of configurations of a polymer is reduced in the presence of a barrier or an obstacle. The resulting loss of entropy adds a repulsive component to other forces generated by interaction potentials. When the obstructions are scale invariant shapes (such as cones, wedges, lines, or planes) t...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2013
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| Online Access: | http://hdl.handle.net/1721.1/77139 https://orcid.org/0000-0002-1112-5912 |
| _version_ | 1826197069658849280 |
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| author | Faghfoor Maghrebi, Mohammad Kantor, Yacov Kardar, Mehran |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Faghfoor Maghrebi, Mohammad Kantor, Yacov Kardar, Mehran |
| author_sort | Faghfoor Maghrebi, Mohammad |
| collection | MIT |
| description | The number of configurations of a polymer is reduced in the presence of a barrier or an obstacle. The resulting loss of entropy adds a repulsive component to other forces generated by interaction potentials. When the obstructions are scale invariant shapes (such as cones, wedges, lines, or planes) the only relevant length scales are the polymer size R[subscript 0] and characteristic separations, severely constraining the functional form of entropic forces. Specifically, we consider a polymer (single strand or star) attached to the tip of a cone, at a separation h from a surface (or another cone). At close proximity, such that h≪R[subscript 0], separation is the only remaining relevant scale and the entropic force must take the form F=Ak[subscript B]T/h. The amplitude A is universal and can be related to exponents η governing the anomalous scaling of polymer correlations in the presence of obstacles. We use analytical, numerical, and ε-expansion techniques to compute the exponent η for a polymer attached to the tip of the cone (with or without an additional plate or cone) for ideal and self-avoiding polymers. The entropic force is of the order of 0.1 pN at 0.1 μm for a single polymer and can be increased for a star polymer. |
| first_indexed | 2024-09-23T10:42:01Z |
| format | Article |
| id | mit-1721.1/77139 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:42:01Z |
| publishDate | 2013 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/771392022-09-30T22:21:41Z Polymer-mediated entropic forces between scale-free objects Faghfoor Maghrebi, Mohammad Kantor, Yacov Kardar, Mehran Massachusetts Institute of Technology. Department of Physics Faghfoor Maghrebi, Mohammad Kardar, Mehran The number of configurations of a polymer is reduced in the presence of a barrier or an obstacle. The resulting loss of entropy adds a repulsive component to other forces generated by interaction potentials. When the obstructions are scale invariant shapes (such as cones, wedges, lines, or planes) the only relevant length scales are the polymer size R[subscript 0] and characteristic separations, severely constraining the functional form of entropic forces. Specifically, we consider a polymer (single strand or star) attached to the tip of a cone, at a separation h from a surface (or another cone). At close proximity, such that h≪R[subscript 0], separation is the only remaining relevant scale and the entropic force must take the form F=Ak[subscript B]T/h. The amplitude A is universal and can be related to exponents η governing the anomalous scaling of polymer correlations in the presence of obstacles. We use analytical, numerical, and ε-expansion techniques to compute the exponent η for a polymer attached to the tip of the cone (with or without an additional plate or cone) for ideal and self-avoiding polymers. The entropic force is of the order of 0.1 pN at 0.1 μm for a single polymer and can be increased for a star polymer. National Science Foundation (U.S.) (Grant PHY05-51164) National Science Foundation (U.S.) (Grant DMR-12-06323) 2013-02-15T15:02:27Z 2013-02-15T15:02:27Z 2012-12 2012-08 Article http://purl.org/eprint/type/JournalArticle 1539-3755 1550-2376 http://hdl.handle.net/1721.1/77139 Maghrebi, Mohammad F., Yacov Kantor, and Mehran Kardar. “Polymer-mediated Entropic Forces Between Scale-free Objects.” Physical Review E 86.6 (2012). ©2012 American Physical Society https://orcid.org/0000-0002-1112-5912 en_US http://dx.doi.org/10.1103/PhysRevE.86.061801 Physical Review E Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Faghfoor Maghrebi, Mohammad Kantor, Yacov Kardar, Mehran Polymer-mediated entropic forces between scale-free objects |
| title | Polymer-mediated entropic forces between scale-free objects |
| title_full | Polymer-mediated entropic forces between scale-free objects |
| title_fullStr | Polymer-mediated entropic forces between scale-free objects |
| title_full_unstemmed | Polymer-mediated entropic forces between scale-free objects |
| title_short | Polymer-mediated entropic forces between scale-free objects |
| title_sort | polymer mediated entropic forces between scale free objects |
| url | http://hdl.handle.net/1721.1/77139 https://orcid.org/0000-0002-1112-5912 |
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