SWELLING BEHAVIOR OF THERMOSENSITIVE N-ISOPROPYLACRYLAMIDE-ETHYL N-ACRYLOYLGLYCINE SUBMICRON-SIZED COPOLYMER GEL PARTICLES

Submicron-sized N-isopropylacrylamide (MPA)-ethyl N-acryloylglycine (E NAG) copolymer gel particles with various compositions were prepared b y precipitation polymerization in water. Their swelling behaviors were determined by photon correlation spectroscopy(PCS). Our results showe d that the volume transition temperature of copolymer gel particles de creased with increasing the mole ratio of ENAG. In model development, we modified the extended Flory-Huggins theory as a free energy of mixi ng term and employed the modified Flory-Rehner theory for the elastic contribution and compared the proposed model with our swelling data. T he model predicted fairly well the swelling behaviors of copolymer gel particles. (C) 1998 John Wiley & Sons, Inc.