Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness
Quite often polymers exhibit different elastic behavior depending on the statistical ensemble (Gibbs vs. Helmholtz). This is an effect of strong fluctuations. In particular, two-state polymers, which locally or globally fluctuate between two classes of microstates, can exhibit strong ensemble inequi...
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| Format: | Article |
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MDPI AG
2023-05-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/10/2307 |
| _version_ | 1797598561000488960 |
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| author | Mohammadhosein Razbin Panayotis Benetatos |
| author_facet | Mohammadhosein Razbin Panayotis Benetatos |
| author_sort | Mohammadhosein Razbin |
| collection | DOAJ |
| description | Quite often polymers exhibit different elastic behavior depending on the statistical ensemble (Gibbs vs. Helmholtz). This is an effect of strong fluctuations. In particular, two-state polymers, which locally or globally fluctuate between two classes of microstates, can exhibit strong ensemble inequivalence with negative elastic moduli (extensibility or compressibility) in the Helmholtz ensemble. Two-state polymers consisting of flexible beads and springs have been studied extensively. Recently, similar behavior was predicted in a strongly stretched wormlike chain consisting of a sequence of reversible blocks, fluctuating between two values of the bending stiffness (the so called reversible wormlike chain, rWLC). In this article, we theoretically analyse the elasticity of a grafted rod-like semiflexible filament which fluctuates between two states of bending stiffness. We consider the response to a point force at the fluctuating tip in both the Gibbs and the Helmholtz ensemble. We also calculate the entropic force exerted by the filament on a confining wall. This is done in the Helmholtz ensemble and, under certain conditions, it yields negative compressibility. We consider a two-state homopolymer and a two-block copolymer with two-state blocks. Possible physical realizations of such a system would be grafted DNA or carbon nanorods undergoing hybridization, or grafted F-actin bundles undergoing collective reversible unbinding. |
| first_indexed | 2024-03-11T03:22:54Z |
| format | Article |
| id | doaj.art-e5e52c6a3cc040d6839d28a39628bd0d |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T03:22:54Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-e5e52c6a3cc040d6839d28a39628bd0d2023-11-18T02:58:13ZengMDPI AGPolymers2073-43602023-05-011510230710.3390/polym15102307Elasticity of a Grafted Rod-like Filament with Fluctuating Bending StiffnessMohammadhosein Razbin0Panayotis Benetatos1Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 14588, IranDepartment of Physics, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of KoreaQuite often polymers exhibit different elastic behavior depending on the statistical ensemble (Gibbs vs. Helmholtz). This is an effect of strong fluctuations. In particular, two-state polymers, which locally or globally fluctuate between two classes of microstates, can exhibit strong ensemble inequivalence with negative elastic moduli (extensibility or compressibility) in the Helmholtz ensemble. Two-state polymers consisting of flexible beads and springs have been studied extensively. Recently, similar behavior was predicted in a strongly stretched wormlike chain consisting of a sequence of reversible blocks, fluctuating between two values of the bending stiffness (the so called reversible wormlike chain, rWLC). In this article, we theoretically analyse the elasticity of a grafted rod-like semiflexible filament which fluctuates between two states of bending stiffness. We consider the response to a point force at the fluctuating tip in both the Gibbs and the Helmholtz ensemble. We also calculate the entropic force exerted by the filament on a confining wall. This is done in the Helmholtz ensemble and, under certain conditions, it yields negative compressibility. We consider a two-state homopolymer and a two-block copolymer with two-state blocks. Possible physical realizations of such a system would be grafted DNA or carbon nanorods undergoing hybridization, or grafted F-actin bundles undergoing collective reversible unbinding.https://www.mdpi.com/2073-4360/15/10/2307wormlike chainelasticitystatistical ensemble inequivalencenegative compressibility |
| spellingShingle | Mohammadhosein Razbin Panayotis Benetatos Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness Polymers wormlike chain elasticity statistical ensemble inequivalence negative compressibility |
| title | Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness |
| title_full | Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness |
| title_fullStr | Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness |
| title_full_unstemmed | Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness |
| title_short | Elasticity of a Grafted Rod-like Filament with Fluctuating Bending Stiffness |
| title_sort | elasticity of a grafted rod like filament with fluctuating bending stiffness |
| topic | wormlike chain elasticity statistical ensemble inequivalence negative compressibility |
| url | https://www.mdpi.com/2073-4360/15/10/2307 |
| work_keys_str_mv | AT mohammadhoseinrazbin elasticityofagraftedrodlikefilamentwithfluctuatingbendingstiffness AT panayotisbenetatos elasticityofagraftedrodlikefilamentwithfluctuatingbendingstiffness |