Knots “choke off” polymers upon stretching
Long polymer chains inevitably get tangled into knots. Like macroscopic ropes, polymer chains are substantially weakened by knots and the rupture point is always located at the “entry” or “exit” of the knot. However, these phenomena are only poorly understood at a molecular level. Here we show that...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
5 January 2016
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| In: |
Angewandte Chemie. International edition
Year: 2016, Volume: 55, Issue: 2, Pages: 811-814 |
| ISSN: | 1521-3773 |
| DOI: | 10.1002/anie.201508706 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1002/anie.201508706 Verlag, Volltext: http://onlinelibrary.wiley.com/doi/10.1002/anie.201508706/abstract 
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| Author Notes: | Tim Stauch and Andreas Dreuw |
| Summary: | Long polymer chains inevitably get tangled into knots. Like macroscopic ropes, polymer chains are substantially weakened by knots and the rupture point is always located at the “entry” or “exit” of the knot. However, these phenomena are only poorly understood at a molecular level. Here we show that when a knotted polyethylene chain is tightened, most of the stress energy is stored in torsions around the curved part of the chain. The torsions act as “work funnels” that effectively localize mechanical stress in the immediate vicinity of the knot. As a result, the knot “chokes” the chain at its entry or exit, thus leading to bond rupture at much lower forces than those needed to break a linear, unknotted chain. Our work not only explains the weakening of the polymer chain and the position of the rupture point, but more generally demonstrates that chemical bonds do not have to be extensively stretched to be broken. |
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| Item Description: | First published: 2 December 2015 Gesehen am 07.12.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1521-3773 |
| DOI: | 10.1002/anie.201508706 |