Departmental Papers (CBE)

Document Type

Journal Article

Date of this Version

March 2003


We demonstrate how tracer microrheology methods can be extended to study submicron scale variations in the viscoelastic response of soft materials; in particular, a semidilute solution of lambda-DNA. The polymer concentration is depleted near the surfaces of the tracer particles, within a distance comparable to the polymer correlation length. The rheology of this microscopic layer alters the tracers’ motion and can be precisely quantified using one- and two-point microrheology. Interestingly, we found this mechanically distinct layer to be twice as thick as the layer of depleted concentration, likely due to solvent drainage through the locally perturbed polymer structure.


Copyright American Physical Society. Reprinted from Physical Review Letters, Volume 90, Issue 10, Article 108301, March 2003, 4 pages.
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Date Posted: 20 December 2005

This document has been peer reviewed.