Equilibrium swelling behavior of crosslinked chitosan hydrogels

Chemically and physically crosslinked chitosan hydrogels were obtained by treating chitosan (Ch) with glutaraldehyde (GA) and sodium tripolyphosphate or GA and sodium citrate, GA and sulfuric acid and GA and sulfosuccinic acid, respectively. The formation of covalent and ionic crosslinks between Ch, GA and low molecular ionic compounds was confirmed by FTIR spectroscopy. There was examined the equilibrium degree of swelling of membranes formed from uncrosslinked and crosslinked chitosan hydrogels in buffer solutions of different pH. It was observed that the swelling of all studied membranes was highly dependent on pH.