Effect of cyclic chain architecture on properties of dilute solutions of polyethylene from molecular dynamics simulations Academic Article uri icon

abstract

  • We have used molecular dynamics methods to investigate the effects of cyclic chain architecture on the properties of dilute solutions. In order to include solvent effects in estimating these properties, we use a van der Waals scaling factor determined for each solvent by matching to the theta condition. We predict that the theta temperature () of cyclic PE (c-PE) is 10% lower than for the linear case (l-PE). This can be compared to the experimental results for polystyrene (PS), where for cyclic PS is 2% lower. For conditions corresponding to n-pentane solvent, we predict that Rg2cyclic/Rg2linear is 0.59 for all temperatures above 350 K. The deviation from the ratio of 0.500.53 expected from analytic theory is due to the competition between chain stiffness and excluded volume effects. To calculate the intrinsic viscosity of c-PE and l-PE we extended the BloomfieldZimm type theory to include chain stiffness corrections. We find that for the theta temperature, the ratio of viscosities for c-PE and l-PE is 0.71, which is 7% higher than the value of 0.66 from the freely jointed chain model. This difference is caused by the larger value of Rg2cyclic/Rg2linear from the simulations.

published proceedings

  • The Journal of Chemical Physics

altmetric score

  • 3

author list (cited authors)

  • Jang, S. S., ain, T., & Goddard, W. A.

citation count

  • 40

complete list of authors

  • Jang, Seung Soon||Çağin, Tahir||Goddard, William A

publication date

  • July 2003