Computer simulations of polyisoprene local dynamics in vacuum, solution, and the melt: Are conformational transitions always important?

Macromolecules

Volumn 29, Issue 16, 1996, Pages 5484-5492

  Moe, Neil E ^a   Ediger, M D ^a  

^a UNIVERSITY OF WISCONSIN MADISON   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

CHEMICAL BONDS; COMPUTER SIMULATION; CONFORMATIONS; CORRELATION METHODS; MOLECULAR ORIENTATION; ORGANIC POLYMERS; POLYISOPRENES; RELAXATION PROCESSES; VACUUM; VECTORS;

MELTS; ORIENTATION CORRELATION FUNCTIONS; TORSIONS;

MOLECULAR DYNAMICS;

EID: 0030194830     PISSN: 00249297     EISSN: None     Source Type: Journal    
DOI: 10.1021/ma960204t     Document Type: Article

References (42)

1. Pschorn, U.; Rössler, E.; Sillescu, H.; Kaufmann, S.; Shaefer, D.; Spiess, H. W. Macromolecules 1991, 24, 398.
2. Schaefer, D.; Spiess, H. W.; Suter, U. W.; Fleming, W. W. Macromolecules 1990, 23, 3431.
3. Ferry, J. D.; Fitzgerald, E. R. J. Colloid Sci. 1953, 8, 224.
4. McCrum, N. G.; Read, B. E.; Williams, G. Anelastic and Dielectric Effects in Polymer Solids; Wiley: London, 1967.
5. Jones, A.; Stockmayer, W. J. Polym. Sci., Polym. Phys. Ed. 1977, 15, 847.
6. Bendler, J.; Yaris, R. Macromolecules 1978, 11, 650.
7. Gronski, W.; Makromol. Chem. 1977, 178, 2949.
8. Mclnnes, D.; North, A. Polymer 1977, 18, 505.
9. Anderson, J. J. Chem. Phys. 1970, 52, 2821.
10. Valeur, B.; Jarry, J.; Geny, F.; Monnerie, L. J. Polym. Sci., Polym. Phys. Ed. 1975, 13, 667.
11. Skolnick, J.; Yaris, R. Macromolecules 1983, 16, 266.
12. Helfand, E. J. Polym. Sci., Polym. Symp. 1985, 73, 39.
13. Hall, C. K.; Helfand, E. J. Chem. Phys. 1982, 77, 3275. Cook, R.; Helfand, E. J. Chem. Phys. 1985, 82, 1599. Skolnick, J.; Helfand, E. J. Chem. Phys. 1980, 72, 5489.
14. Hall, C. K.; Helfand, E. J. Chem. Phys. 1982, 77, 3275. Cook, R.; Helfand, E. J. Chem. Phys. 1985, 82, 1599. Skolnick, J.; Helfand, E. J. Chem. Phys. 1980, 72, 5489.
15. Hall, C. K.; Helfand, E. J. Chem. Phys. 1982, 77, 3275. Cook, R.; Helfand, E. J. Chem. Phys. 1985, 82, 1599. Skolnick, J.; Helfand, E. J. Chem. Phys. 1980, 72, 5489.
16. Perico, A. Acc. Chem. Res. 1989, 22, 336.
17. Moro, G. J. Chem. Phys. 1992, 97, 5749.
18. Mashimo, S.; Chiba, A. Polym. J. 1973, 5, 41.
19. Gronski, W.; Schafer, T.; Peter, R. Polym. Bull. 1979, 1, 319.
20. Radiotis, T.; Brown, G. R.; Dias, P. Macromolecules 1993, 26, 1445.
21. Zhu, W.; Gisser, D.; Ediger, M. D. J. Polym. Sci., Part B: Polym. Phys. 1994, 32, 2251.
22. Dejean de la Batie, R.; Lauprêtre, F.; Monnerie, L. Macromolecules 1989, 22, 122.
23. Denault, J.; Prud'homme, J. Macromolecules 1989, 22, 1307.
24. Bandis, A.; Inglefield, P. T.; Jones, A. A.; Wen, W.-Y. J. Polym. Sci., Polym. Phys. Ed. 1995, 33, 1515.
25. Zemke, K.; Chmelka, B. F.; Schmidt-Rohr, K.; Spiess, H. W. Macromolecules 1991, 24, 6874. Schaefer, D.; Spiess H. W. J. Chem. Phys. 1992, 97, 7944.
26. Zemke, K.; Chmelka, B. F.; Schmidt-Rohr, K.; Spiess, H. W. Macromolecules 1991, 24, 6874. Schaefer, D.; Spiess H. W. J. Chem. Phys. 1992, 97, 7944.
27. Adolf, D.; Ediger, M. D. Macromolecules 1991, 24, 5834.
28. Smith, G. D.; Yoon, D. Y.; Zhu, W.; Ediger, M. D. Macromol. ecules 1994, 27, 5563.
29. Mansfield, M. J. Chem. Phys. 1980, 72, 3923.
30. Moe, N.; Ediger, M. D. Polymer 1996, 37, 1787.
31. Moe, N.; Ediger, M. D. Macromolecules 1995, 28, 2329.
32. (a) Maple, J. R.; Dinur, U.; Hagler, A. T. Proc. Natl. Acad. Sci. U.S.A. 1988, 85, 5350.
33. (b) Maple, J. R.; Thacher, T. S.; Dinur, U.; Hagler, A. T. Chem. Des. Automat. News 1990, 5 (9), 5.
34. Biosym Technologies Inc., San Diego, CA.
35. Another important feature of C-H vector correlation functions in the three environments is that they have qualitatively different shapes (see Figure 3). The long-time portion of the decay is nearly single exponential in solution and quite nonexponential in the melt. In this paper, we have not considered the relationship between the mechanism of local polymer dynamics and the C-H vector correlation function shapes.
36. Takeuchi, H.; Roe, R. J. Chem. Phys. 1991, 94, 7446.
37. 90 melts also show quite anisotropic dynamics, although not to the same degree as found by Takeuchi and Roe. Simulations of cis- and trans-polybutadiene melts by Kim and Mattice (Kim, E.-G,; Mattice, W. L. J. Chem. Phys. 1994, 101, 6242) show that the backbone geometry can play a large role: The cis chains were found to have relatively little relaxation anisotropy, similar to our cis-polyisoprene, while the local dynamics of the trans- chains were much more anisotropic.
38. 90 melts also show quite anisotropic dynamics, although not to the same degree as found by Takeuchi and Roe. Simulations of cis- and trans-polybutadiene melts by Kim and Mattice (Kim, E.-G,; Mattice, W. L. J. Chem. Phys. 1994, 101, 6242) show that the backbone geometry can play a large role: The cis chains were found to have relatively little relaxation anisotropy, similar to our cis-polyisoprene, while the local dynamics of the trans- chains were much more anisotropic.
39. trans. The average transition time is calculated using the same equation except that all types of torsions are considered.
40. This was done by subtracting the infinite time values and normalizing the resulting functions (not shown).
41. For the purpose of this calculation, a repeat unit was defined to be the region between double bonds.
42. There were about 10 times more barrier crossings than conformational transitions in the melt and solution, and about 5 times more in vacuum.