Polyelectrolyte complex (PEC) hydrogels composed of various weight ratios of chitosan and hyaluronic acid were prepared. The PEC hydrogels were formed by the reaction of the oppositely charged chitosan polymers. The PEC films swelled in water rapidly, reaching equilibrium within 30 min, and exhibited relatively high swelling ratios, 243-322%, at 25degreesC. The swelling ratio increased with increasing temperature. The transport phenomena of all PEC samples were non-Fickian and diffusion and relaxation controlled. The diffusion coefficients of the PEC films ranged from 2.22 x 10(-6) to 10.05 x 10(-6) cm(2)/s. The activation energy of the polyelectrolyte complexes ranged from 37.14 to 54.58 kJ/mol and proved to be hydrophilic. (C) 2004 Wiley Periodicals, Inc.