Atomistic simulation of energetic and entropic elasticity in short-chain polyethylenes
| Autor: | David J. Keffer, Brian J. Edwards, T. C. Ionescu, Vlasis G. Mavrantzas |
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| Rok vydání: | 2008 |
| Předmět: |
Quantitative Biology::Biomolecules
Materials science Specific heat Mechanical Engineering Monte Carlo method Intermolecular force Non-equilibrium thermodynamics Thermodynamics Statistical mechanics Condensed Matter Physics Heat capacity Linear low-density polyethylene Non newtonian flow Mechanics of Materials General Materials Science |
| Zdroj: | Journal of Rheology. 52:567-589 |
| ISSN: | 1520-8516 0148-6055 |
| DOI: | 10.1122/1.2838250 |
| Popis: | The thermodynamical aspects of polymeric liquids subjected to uniaxial elongational flow are examined using atomistically detailed nonequilibrium Monte Carlo simulations. In particular, attention is paid to the energetic effects, in addition to the entropic ones, which occur under conditions of extreme deformation. Atomistic nonequilibrium Monte Carlo simulations of linear polyethylene systems, ranging in molecular length from C24 to C78 and for temperatures from 300to450K, demonstrate clear contributions of energetic effects to the elasticity of the system. These are manifested in a conformationally dependent heat capacity, which is significant under large deformations. Violations of the hypothesis of purely entropic elasticity are evident in these simulations, in that the free energy of the system is demonstrated to be composed of significant energetic effects under high degrees of orientation. These arise mainly from favorable intermolecular side-to-side interactions developing in the process of elonga... |
| Databáze: | OpenAIRE |
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