Probing the relationship between the scales of space and time in an entangled polymer network with an oscillating nanotip

The dynamical behaviour of an entangled network, a melt made of long polymer chains, with an oscillating nanotip, is investigated to provide evidence for a close relationship between the spatial scale and dynamics of the network, from the molecular to the mesoscopic scale. The experimental results show how a dynamic force microscope is able to discriminate between slow and fast relaxation processes related to molecular motion at different scales. In particular, it is shown that within a very small variation of the tip indentation depth, a few ångströms, the relaxation times involved in the process of dissipation vary by more than three orders of magnitude.