Effect of the water state on the electrical bending behavior of chitosan/poly(diallyidimethylammonium chloride) hydrogels in NaCl solutions

Semi-interpenetrating polymer network (SIPN) hydrogels, composed of chitosan (CS) and poly(diallyldimethylammonium chloride) (PDADMAC), were prepared, and they exhibited electrically sensitive behavior. The swelling behavior of the CS/PDADMAC SIPN hydrogels was studied through the immersion of the gels in various concentrations of aqueous NaCl solutions, and their responses to stimuli in electric fields were also investigated. When the swollen SIPN hydrogels were placed between a pair of electrodes, they exhibited bending behavior upon the application of an electric field, which was stepwise and dependent on the magnitude of the field. To clarify the relationship between the equilibrium-swelling ratio and the bending behavior of the SIPN hydrogels, the state of water in the SIPN hydrogels was also investigated with differential scanning calorimetry. (C) 2004 Wiley Periodicals, Inc.