Swelling behavior of N-isopropylacrylamide gel particles with degradable crosslinker

We prepared submicron sized N-isopropylacrylamide gel particles using a deg radable crosslinker based on phosphazene derivatives. N,N'-methylenebisacry lamide, tri(ethylene glycol) dimethylacrylate and 1,4-butanediol diacrylate were also used as nondegradable crosslinkers. Swelling ratios of gel parti cles were determined by the photon correlation spectroscopy (PCS) technique . Gel network degradation was characterized by measuring swelling ratios wi th continued exposure to water. Gel particles crosslinked with phosphazene trimer crosslinker degraded within 10 days, because of the hydrolysis of th e crosslinker. The swelling behavior of each gel particle represents contin uous volume phase transition. The degree of swelling ratio of gel particles crosslinked with a degradable crosslinker is less than that of gel particl es crosslinked with nondegradable crosslinkers. We employed the thermodynam ic model based on Bae et al, and successfully describe the swelling behavio rs of gel particles. (C) 1999 Elsevier Science Ltd. All rights reserved.