Using glycidyl methacrylate as cross-linking agent to prepare thermosensitive hydrogels by a novel one-step method

A novel one-step approach is reported to prepare thermosensitive hydrogels simply by using hydroxypropyl-p-cyclodextrin (HP-beta-CD)/glycidyl methaerylate (GMA)/N-isopropylacrylamide (NIPAM) system. From GMA and HP-beta-CD, HP-beta-CD/ GMA inclusion complex was prepared and identified with NMR, FTIR, and UV-vis spectroscopies. GMA in the form of HP-beta-CD/GMA complex was copolymerized with NIPAM in water with K2S2O8 as initiator, yielding hydrogels designated as poly(NlPAM-CD-GMA). The inclusion of CD in the hydrogels was confirmed by FTIR spectroscopy. The contents of CD and GMA placed considerable influence on the swelling ratio and temperature-sensitivity of the produced hydrogels. The hydrogels bearing CD moieties showed higher swelling ratio and temperature-sensitivity when compared with that without CD. The porous structure of the hydrogels containing CD was observed in the SEM images. Relevant mechanism of the ring-opening reaction of epoxide groups in GMA, the subsequent crosslinking reactions and the formation of hydrogels containing CD moieties were proposed. (c) 2008 Wiley Periodicals, Inc.