Molecular dynamics simulations ofn-Alkane melts confined between solid surfaces
| Autor: | Do Y. Yoon, Roland G. Winkler, Peter Reineker, Tsunetoshi Matsuda, Anja Gerstmair |
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| Rok vydání: | 1994 |
| Předmět: |
chemistry.chemical_classification
Self-diffusion Polymer Condensed Matter Physics Fick's laws of diffusion Atomic and Molecular Physics and Optics Molecular dynamics chemistry.chemical_compound Monomer Adsorption chemistry Computational chemistry Chemical physics Atom Molecule Physical and Theoretical Chemistry |
| Zdroj: | International Journal of Quantum Chemistry. 52:437-456 |
| ISSN: | 1097-461X 0020-7608 |
| DOI: | 10.1002/qua.560520216 |
| Popis: | Molecular dynamics simulations of polyethylene chains (C{sub n}H{sub 2n+2} for n = 13, 16, 28, 60) have been carried out to investigate both equilibrium and dynamic properties of polymer melts confined between flat solid surfaces. The authors observe an oscillatory monomer density in the direction normal to the solid surfaces, which depends on the size of the monomers (i.e., on the volume density of the system). The packing manner of monomer segments, segment orientation, and local conformations of chains are found to be independent of chain length. In addition, preferential interfacial adsorption of chain ends is observed. The chains are flattened close to the surface and many molecules assume essentially two-dimensional train configurations even in the case of C{sub 60}H{sub 122} melts. The apparent self-diffusivities of the centers of mass of the molecules depend on their distance from a surface. Molecules adjacent to a surface exhibit a reduced mobility perpendicular to the surface and an increased one parallel to it. The self-diffusion constant parallel to a surface depends strongly on the size of the monomers. An increase of the united atom diameter by 10% reduces the diffusion constant by a factor of three, in good agreement with the experimental value.more » 49 refs., 11 figs.« less |
| Databáze: | OpenAIRE |
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