How does Sodium Polyacrylate Work?

How does sodium polyacrylate work? Superabsorbent polymers are partially neutralized polyacrylate, with incomplete cross-linking between units. Only 50-70% of the COOH acid groups have been converted to their sodium salts. The final chemical has very long carbon chains bonded with sodium atoms in the center of the molecule. When sodium polyacrylate is exposed to water, the higher concentration of water outside the polymer than inside draws the water into the center of the molecule via osmosis.