Steady-state properties and dynamic behavior of polymer chains in dilute solution under elongational flow

The behavior of polymer chains in dilute solution under a steady, homogeneo us elongational flow has been studied employing Brownian dynamics simulatio n. We first consider the dependence of polymer properties in steady state o n the elongational rate, epsilon. When this rate exceeds some critical valu e, epsilon(c), the properties show a dramatic change from the values typica l of the coil state to those of a stretched conformation. We describe the d ependence of epsilon(c) on chain length for different polymer/solvent condi tions. Following the trajectories of individual molecules, we have characte rized dynamic aspects of the coil-stretch transition. Each chain suffer the transition after some time, t(trans), has elapsed after the flow start-up. The values of t(trans), vary remarkably from one molecule to another, and we have characterized the statistical distribution of this quantity. We als o determine the kinetics of the coil-to-stretch process, which seems to fol low a first-order kinetics after some induction time. The dependence of the statistical and kinetic parameters on chain length and elongational rate h as been determined.