Surface response of a semi-infinite polymer network

  Chen Bar-Haim  ,  Haim Diamant  
Tel Aviv University

We study theoretically the surface response of a semi-infinite viscoelastic polymer

network using the two-fluid model. We focus on the overdamped limit and on the

effect of network's intrinsic length scales. We calculate the decay rate of slow

surface fluctuations, and the surface displacement in response to a localized force.

Deviations from the large-scale continuum response are found at length scales much

larger than the network's mesh size. We discuss implications for surface scattering

and microrheology. We provide closed-form expressions that can be used for surface

microrheology - the extraction of viscoelastic moduli and intrinsic length scales from

the motions of tracer particles lying on the surface without doping the bulk material.