Cure Terms Glossary

Hydrogels


Hydrogels are formed when hydrophilic polymers absorb water to an equilibrium value - where the extent of water uptake results from the balance between the osmotic forces leading to swelling and the forces exerted by the polymer chains in resisting expansion. Covalent crosslinking in the hydrophilic polymer will limit the extent of solvation in this way, as will other polymer-polymer interactions such as can be achieved by introducing hydrophobic segments into block copolymers.

Hydrogels are encountered in a range of applications from the mundane (e.g. hair gel) to the specialised (e.g. tissue scaffolds). Water can be present in various states of association (including directly H-bonded to the polymer). That not directly associated with the polymer (i.e. freely diffusible water) allows for migration of water-soluble species and creates products with applications in controlled release.