Anomalous diffusion of poly(ethylene oxide) in agarose gels

We report on the effect of probe size and diffusion time of poly(ethylene) oxide in agarose gels. Time dependence of the diffusion coefficient, reflecting anomalous diffusion, was observed for poly(ethylene) oxide chains with hydrodynamic radii exceeding about 20 nm at an agarose concentration of 2%. The main conclusion is that the pore distribution includes pores that are only several nm across, in agreement with scattering reports in the literature. Interpretation of the diffusion coefficient dependence on the probe size based on a model of entangled rigid rods yielded a rod length of 72 nm. (C) 2016 Published by Elsevier B.V.