SWELLING EQUILIBRIA AND VOLUME PHASE-TRANSITION OF POLYELECTROLYTE GEL WITH STRONGLY DISSOCIATED GROUPS

The peculiarities of the swelling equilibrium and volume phase transit ion of polyelectrolyte copolymer gels consisting of acrylamide and 2-a crylamido-2-methyl-1-propane sulphonic acid (AAm/AMPS) have been studi ed as a function of copolymer composition and gel structure. Equilibri um swelling for AAm/AMPS gels in buffer solutions, pure water and aque ous salt (NACl) solutions were investigated. The swelling curves were calculated using the Hasa-Ilavsky-Dusek theory and obtained experiment ally. The agreement is reasonably goon, and the HID theory can be used to estimate the swelling and structural parameter of AAm/AMPS gels. T he volume phase transition has been generated by changing the solvent composition by progressive substitution of water by acetone. The criti cal interaction parameter corresponding to collapse depends strongly o n the composition of the gel, since the extent of collapse is determin ed by composition and cross-link density of the gel. (C) 1998 Elsevier Science Ltd. All rights reserved.