A series of ionically crosslinked polyampholyte hydrogels were prepared by free radical aqueous copolymerization of acrylamide and the ionic complex of(N

N-diethylamino)ethyl methacrylate and acryl；cacid (poly(acrylamide-co-N

N-diethylaminoethyl methacrylate-co—acrylic acid)

designated as PADA)．The investigation indicated that PADA gels exhibited peculiar erosion phenomenon under non—contact direct current electric fields．The erosin rate of PADA gels was related to the voltage of electric field

the concentration of salt solution

pH value of buffer solution．the molar ratio of anionic／cationic monomers

valence of ion and so on．For instance

the erosion rate increased with an increase of voltage or the concentration of salt solution．The erosion kinetics revealed that the erosion rate of PADA gels was almost invariable in experiments．