Conformation and dynamics of star-branched flexible polymer chains in a flowing solution

摘要

When linear or star-branched polymer chains in dilute solution are subjected to extensional flow of adequate intensity, each chain in the sample experiences a coil-stretch transition. Using Brownian dynamics simulation, we have studied both static and dynamic aspects of this phenomenon. We have determined the power law that relates the critical extensional rate,,, to the molecular weight of the chain. In the case of linear chains we have studied the distribution of transition times. If the accumulated strain is used to characterize the flow effect a seemingly universal behavior, independent of molecular weight is found. The molecular individualism is related to the excess of the applied extensional rate over its critical value, which will determine the transition time and other features of the coil-stretch transition. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 20]