Surface grafting polymerization and crosslinking of thermosensitive NIPAAm hydrogels onto plasma pretreated substrates and drug delivery properties

Poly (N-isopropylacrylamide) (PNIPAAm) hydrogel has a lower critical solution temperature (LCST), and exhibits a discontinuous volume phase transition in response to a small temperature change. PNIPAAm have been widely investigated in the fields of drug-delivery systems, diagnostics, bioreactors, cell culture and bioseperations. Since the mechanical strength of hydrogels with high water content is not enough for its application, therefore PNIPAAm gel have been grafted onto the polymers to improve mechanical properties. Photo-induced graft polymerization of NIPAAm with plasma pretreatment on PP non-woven was carried out at 65degreesC in a water medium. The effect of crosslinking density on drug release behavior of the nonwoven-gel composites was investigated by preparing the hydrogels with various crosslinking densities. The results shown that the nonwoven-gel composites exhibited a fast temperature-responsive character and that the crosslinking density strongly affected the swelling ratio and drug release ratio but not change the LCST of the hydrogels.