Polymer Science Faculty Research


Observations of wall slip and shear banding in an entangled DNA solution

Document Type


Publication Date

Spring 2008


We have studied nonlinear flow behavior of entangled DNA solutions using particle tracking velocimetry in Couette and cone/plate geometries. At apparent shear rate γ̇app < 0.1 s−1, the velocity profile is linear across the gap. Beyond the terminal region with γ̇app < 40 s−1, the velocity profile becomes temporarily banded after the stress maximum and shows massive wall slip at long times with little shear banding in the bulk. At γ̇app > 40 s−1, the velocity profile progressively curves and becomes banded with a sharp interface after hundreds of strain units. In the steady state, the thickness of high-shear band increases linearly with the apparent shear rate. At γ̇app = 1000 s−1, the velocity profile returns to linearity.



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