Hydrogels are water-swollen, cross-linked polymeric structures produced by reactions of monomers or by hydrogen bonding. Hydrogels are composed of two constituents. One constituent is hydrophilic polymers like polyvinyl alcohol,sodium polyacrylate, acrylate polymers and copolymers, while the second constituent is water.
Hydrogels possess the hydrophilic quality which makes them a good analog for natural tissues and they even tend to mimic the flexibility and other textural qualities of biological media.
Cross linked structure of hydrogels is characterized by junctions or tie points, which may be formed from strong chemical linkages (such as covalent and ionic bonds), permanent or temporary physical entanglements, microcrystallite formation, and weak interactions (such as hydrogen bonds).
Hydrogels under mechanical stress can exhibit a range of responses from rapid, elastic recovery following an applied stress or strain to a time-dependent recovery approaching viscous behaviour.
No comments:
Post a Comment