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Sorichetti V, Ninarello A, Ruiz-Franco JM, Hugouvieux V, Kob W, Zaccarelli E, Rovigatti L. Effect of Chain Polydispersity on the Elasticity of Disordered Polymer Networks. Macromolecules 2021; 54:3769-3779. [PMID: 34054144 PMCID: PMC8154883 DOI: 10.1021/acs.macromol.1c00176] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/20/2021] [Indexed: 12/15/2022]
Abstract
Due to their unique structural and mechanical properties, randomly cross-linked polymer networks play an important role in many different fields, ranging from cellular biology to industrial processes. In order to elucidate how these properties are controlled by the physical details of the network (e.g., chain-length and end-to-end distributions), we generate disordered phantom networks with different cross-linker concentrations C and initial densities ρinit and evaluate their elastic properties. We find that the shear modulus computed at the same strand concentration for networks with the same C, which determines the number of chains and the chain-length distribution, depends strongly on the preparation protocol of the network, here controlled by ρinit. We rationalize this dependence by employing a generic stress-strain relation for polymer networks that does not rely on the specific form of the polymer end-to-end distance distribution. We find that the shear modulus of the networks is a nonmonotonic function of the density of elastically active strands, and that this behavior has a purely entropic origin. Our results show that if short chains are abundant, as it is always the case for randomly cross-linked polymer networks, the knowledge of the exact chain conformation distribution is essential for correctly predicting the elastic properties. Finally, we apply our theoretical approach to literature experimental data, qualitatively confirming our interpretations.
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Affiliation(s)
- Valerio Sorichetti
- Laboratoire
de Physique Théorique et Modéles Statistiques (LPTMS), CNRS, Université Paris-Saclay, F-91405 Orsay, France
- Laboratoire
Charles Coulomb (L2C), University of Montpellier,
CNRS, F-34095 Montpellier, France
- IATE,
University of Montpellier, INRAE, Institut Agro, F-34060 Montpellier, France
| | - Andrea Ninarello
- CNR-ISC
Uos Sapienza, Piazzale
A. Moro 2, IT-00185 Roma, Italy
- Department
of Physics, Sapienza Università di
Roma, Piazzale A. Moro
2, IT-00185 Roma, Italy
| | - José M. Ruiz-Franco
- CNR-ISC
Uos Sapienza, Piazzale
A. Moro 2, IT-00185 Roma, Italy
- Department
of Physics, Sapienza Università di
Roma, Piazzale A. Moro
2, IT-00185 Roma, Italy
| | - Virginie Hugouvieux
- IATE,
University of Montpellier, INRAE, Institut Agro, F-34060 Montpellier, France
| | - Walter Kob
- Laboratoire
Charles Coulomb (L2C), University of Montpellier,
CNRS, F-34095 Montpellier, France
- Institut
Universitaire de France, 75005 Paris, France
| | - Emanuela Zaccarelli
- CNR-ISC
Uos Sapienza, Piazzale
A. Moro 2, IT-00185 Roma, Italy
- Department
of Physics, Sapienza Università di
Roma, Piazzale A. Moro
2, IT-00185 Roma, Italy
| | - Lorenzo Rovigatti
- CNR-ISC
Uos Sapienza, Piazzale
A. Moro 2, IT-00185 Roma, Italy
- Department
of Physics, Sapienza Università di
Roma, Piazzale A. Moro
2, IT-00185 Roma, Italy
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