Synthesis and swelling characteristics of poly (N-isopropylacrylamide) temperature sensitive hydrogels crosslinked by electron beam irradiation

Temperature sensitive fast response poly (N-isopropylacrylamide) (PNIPAAm) hydrogels have been synthesized by simultaneously polymerizing and crosslin king NIPAAm monomer in aqueous solutions by electron beam (EB) and gamma ir radiation and their equilibrium and dynamic swelling behavior have been inv estigated. The weight change kinetic studies show that radiation crosslinke d hydrogels swell/deswell to attain equilibrium at much faster rate with di ffusion coefficient values D approximate to 4.0 x 10(-7) cm(2)s(-1) and 15 x 10(-5) cm(2)s(-1) for swelling and deswelling respectively. The effect of radiation characteristics such as irradiation dose, dose rate on the lower critical solution temperature (LCST), gelation dose (D-g) and swelling beh avior of the resultant PNIPAAm gels has also been investigated. (C) 2000 El sevier Science Ltd. All rights reserved.