P(AA-co-DMMAC) hydrogels were synthesized by γ ray irradiation polymerization. The pH value responsive behaviors of hydrogels with different monomer ratios of (DMMC:AA) was studied. When the ratios were 1:3

1:4

1:5

and 1:6

the response behaviors was similar. At pH=7

the gels had large swelling properties

while at higher and lower pH values

the swelling was smaller. The situation was reversed when the monomer ratio was 1:2.