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Research » Polymer Conformational Hysteresis in Mixed Flows

Polymer Conformational Hysteresis in Mixed Flows

We aim to study the non equilibrium behavior of polymer molecules in flows of dilute solution. It has been shown that polymers undergo a coil-to-stretch transition (unraveling) in extensional flow. In addition, this transition exhibits a hysteresis; that is, both the coiled state and the extended state can co-exist at the same flow strength, depending on initial conditions. This transition can be analyzed as a pseudo first order phase transition by calculating an effective energy barrier between the two states, and the rate of state hopping can be obtained. We wish to develop a rate theory for the coil to stretch transition in more general mixed (extensional + vortical) flows and analyze the effective conformational energy barrier as a function of flow mixedness. To accomplish this task, we are performing Brownian dynamics computer simulations coupled with single molecule fluorescence experiments using DNA as a model polymer. These BD simulations are able to capture essential polymer dynamics, including hydrodynamic interactions and the coil-to-stretch hysteresis.

Page last modified on October 10, 2007, at 03:46 PM