Superabsorbent polymers (SAPs) consist of hydrophilic cross-linked polymer networks that can absorb and retain a great amount of water relative to their own mass, so that they are widely used for diapers and drug delivery media. We examine the water a...
Superabsorbent polymers (SAPs) consist of hydrophilic cross-linked polymer networks that can absorb and retain a great amount of water relative to their own mass, so that they are widely used for diapers and drug delivery media. We examine the water absorption of sodium polyacrylate through its swelling. We experimentally observed the one- and two-dimensional swelling of sodium polyacrylate in confined channels. Sodium polyacrylates are typically used in the form of grain to increase the surface area, and our systematic experiments show the dependence of swelling on the size of the grains. The results provide the basis of the hydrodynamic analysis of the water flow through hydrogels with expansion.