Brownian dynamics simulation of a polymer molecule in solution under elongational flow

U. S. Agarwal, Rohit Bhargava, R. A. Mashelkar

Research output: Contribution to journalArticle

Abstract

We use Brownian dynamics simulation to study coil-stretch transition of macromolecules in solution. Into a simple elongational flow field, we introduce freely jointed bead-rod chain model molecules in their coiled and stretched states, and follow the conformational changes. We find good agreement of our simulation results with the available theoretical predictions for low and high strain rates (ε̇). At the intermediate elongation rates (near the onset of coil-stretch transition) of the flow field, we find that the residence time required for stretching of an initially coiled chain can be extremely large as compared to predicted (1 + ln(√N))ε̇-1, especially for the non-free-draining case. Hence, the chain conformation is dependent on the initial state of the chain molecule for residence time as long as 100ε̇-1. Thus, hysteresis is predicted when chain residence time in such an elongational flow field is limited, as in practical situations. Further, at such intermediate ε̇, the chain molecule is seen to undergo Brownian fluctuation induced jumps between a randomly coiled state and another partially stretched state. This suggests the existence of more than one equilibrium conformation that is unstable to Brownian fluctuations.

Original languageEnglish (US)
Pages (from-to)1610-1617
Number of pages8
JournalJournal of Chemical Physics
Volume108
Issue number4
DOIs
StatePublished - Jan 22 1998
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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