Shear-flow-induced unfolding of polymeric globules.
The behavior of a single collapsed polymer under shear flow is examined using hydrodynamic simulations and scaling arguments. Below a threshold shear rate gamma[.]{*}, the chain remains collapsed and only deforms slightly, while above gamma[.]{*} the globule exhibits unfolding/refolding cycles. Hydrodynamics are crucial: In the free draining case, gamma[.]{*} scales with the globule radius R as gamma[.]{*} approximately R{-1}, while in the presence of hydrodynamic interactions gamma[.]{*} approximately R. Experiments on the globular von Willebrand protein confirm the presence of an unfolding transition at a well-defined critical shear rate.
Alexander-Katz
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A
Physics Department, Technical University Munich, 85748 Garching, Germany.
Schneider
M F
MF
Schneider
S W
SW
Wixforth
A
A
Netz
R R
RR
D006801:Humans; D007700:Kinetics; D015233:Models, Statistical; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D013314:Stress, Mechanical; D013997:Time Factors; D014841:von Willebrand Factor / Q000737:chemistry
D011108:Polymers; D014841:von Willebrand Factor