Acrylic acid and methacrylic acid based hydrogels-A review

Hydrogels are three-dimensional polymeric networks those swell quickly by imbibing a large amount of water or deswell in response to even miniscule changes in their external environment. The water uptake or swelling may be thousands of times of their initial volume in water. The volume phase transitions as a response to different stimuli make these materials interesting objects of scientific observations and useful materials for use in advanced technologies. These materials have earned the sobriquet of stimuli responsive or smart gels. The stimulus response of the gels makes these potential materials for uses in variety of applications. Due to their stimuli responsiveness these gels are used in diverse fields such as environment management technologies, controlled drug release, chemomechanical acuator, bioreactor, solute recovery reagent, environment sensitive membrane, mass separation devices, chemical valves, biosensors and in separation and enrichment technologies. In the present review, an attempt has been made to highlight the recent advances in the hydrogels of acrylic acid (AAc) and methacrylic acid