Polyacrylonitrile (PAN) was grafted onto carboxymethyl cellulose (CMC) sodium salt backbones by using ceric ammonium nitrate (CAN) as an initiator. The graft copolymer, CMC-g-PAN, was hydrolyzed by NaOH solution to yield hydrogel, H-CMC-g-PAN. The nitrile groups of CMC-g-PAN were completely converted to a mixture of hydrophilic carboxamide and carboxylate groups during alkaline hydrolysis, followed by in situ crosslinking of the grafted PAN chains. The structure of the products was confirmed by FTIR spectroscopy. The synthetic parameters affecting the swelling capacity of the hydrogel (i.e., CMC-g-PAN add-on value, the hydrolysis time and temperature, and concentration of NaOH) were systematically optimized to achieve maximum swelling. Absorbency was also measured in various salt solutions. The H-CMC-g-PAN product was recognized to be a smart hydrogel with superswelling properties. Several swelling changes of the hydrogel were observed in lieu of pH variations in a wide range (1-13). Also, the pH reversibility and on-off switching behavior make the hydrogel a good candidate for controlled delivery of bioactive agents. (c) 2006 Wiley Periodicals, Inc.