where 𝐷 0 is the self-diffusion coefficient in aqueous solution, 𝑅 ℎ is the hydrodynamic radius of the diffusion probe, 𝑅 𝑓 is the radius of the polymer network fibers, 𝜑 is the volume fraction of network. In the model the diffusion probe is assumed to be spherical and the network is described as a random meshwork of randomly distributed straight fibers; 𝑟̅ is calculated as the largest radius of sphere that on the average can fit into the network structure without touching fibers . Eq. ( )