Simulation of polymers in dilute solution under elongational flow

Abstract

The behavior of polymer chains, modeled as chains of finitely extensible non-linear elastic springs, in solutions undergoing elongational flow, has been studied by Brownian dynamics simulation. The coil–stretch transition is observed when the elongational rate, ϵ ̇ , exceeds some critical ϵ ̇ c that is determined, in steady-state condition, as a function of chain length. We have simulated the time dependence of polymer dimensions when ϵ ̇ is increased from below to above ϵ ̇ c , and then decreased to the initial value. In the coil-to-stretch transition there is an induction time, required to observe the onset of the transition, which varies among the chains in a sample. However, the stretch-to-coil transition follows the same path for all the molecules. The observable properties (sample averages) show a hysteresis cycle that is intensified by the effect of hydrodynamic interaction (HI).