Hydrogels

**Definition:** Water swollen, rigid, 3-dimensional network of cross-linked, hydrophilic macromolecules, 20-95% water. They are used in paints, printing inks, foodstuffs, pharmaceuticals, and cosmetics. (Grant & Hackh's Chemical Dictionary, 5th ed)

**Tree numbers:** - D20.280.320.375 - D26.255.165.320.375

**Synonyms:** - Hydrogel