High resolution shear profile measurements in entangled polymers.
We use confocal microscopy and particle image velocimetry to visualize motion of 250-300 nm. fluorescent tracer particles in entangled polymers subject to a rectilinear shear flow. Our results show linear velocity profiles in polymer solutions spanning a wide range of molecular weights and number of entanglements (8< or =Z< or =56), but reveal large differences between the imposed and measured shear rates. These findings disagree with recent reports that shear banding is a characteristic flow response of entangled polymers, and instead point to interfacial slip as an important source of strain loss.
Hayes
Keesha A
KA
School of Chemical & Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA.
Buckley
Mark R
MR
Cohen
Itai
I
Archer
Lynden A
LA