Diffusion of compact macromolecules through polymer meshes: mesh dynamics and probe dynamics

The diffusion of compact macromolecules in polymer networks is examined to understand how polymer networks or gels could be used to filter different types of macromolecules. We present new measurements of the network and probe dynamics by neutron spin-echo spectroscopy (NSE). The investigated system consists of the protein a-lactalbumin (R-g = 15.2 Angstrom) as probe and a network of high molecular weight polyethylenoxide. The high molecular weight ensures a long disentanglement time for the polymer in order to create a stable network. We compare the network dynamics and the dynamics of the probe protein in the network at different mesh sizes. We study the dynamics at different q values between 0.03 and 0.22 Angstrom(-1). The corresponding length scales reach from distances smaller than the mesh size to larger than the mesh size. (C) 2004 Elsevier B.V. All rights reserved.