Superabsorbent polymers (SAPs) can absorb and retain extremely large amounts of a liquid relative to their own mass

    Water-absorbing polymers, which are classified as hydrogels when cross-linked,[2] absorb aqueous solutions through hydrogen bonding with water molecules. A SAP's ability to absorb water is a factor of the ionic concentration of the aqueous solution. In deionized and distilled water, a SAP may absorb 300 times its weight (from 30 to 60 times its own volume) and can become up to 99.9% liquid, but when put into a 0.9% saline solution, the absorbency drops to maybe 50 times its weight. The presence of valence cations in the solution impedes the polymer's ability to bond with the water molecule.