Estimation of the generation and the weight fraction of dense polymer regions in heterogeneous hydrogels

The internal structure of polyacrylamide gels consists of polymer-dense regions with different densities, which are denoted as "blobs". The density difference between these blobs decreases when a gel is doped with charged molecules. When a small potential is applied between the ends of such a gel, ionic charge carriers result in a current. A theoretical approach is developed to estimate the weight fraction and the number of blob generation. The current decreases with time as a series of exponentially decreasing terms where the exponent and the multiplier of each term measure the density of the blob and the weight fraction of the corresponding blob generation. A theoretical approximation for estimating the density distribution and weight fraction of dense polymer clusters, so-called "blobs", in polyacrylamide hydrogels is developed and confirmed by direct-current measurements. The normalized current density decreases with time as a series of exponentially decreasing terms.