A series of electric field sensitive copolymer P(AA-co-AAEM) gels of acrylic acid (AA) with acetoacetoxy ethyl methacrylate (AAEM) were prepared by free-radical copolymerization, with N,N'-methylene bisacrylamide (MBAAm) and and ammounium persulfate (APS) as crosslinking agent and initiator, respectively. The structures and properties of the gels were tunable by changing the monomer feed weighty ratio (R) (R = W-AAEM/(W-AAEM + W-AA) of AAEM and AA. The influences of the NaCl concentration and pH buffer solutions on the equilibrium swelling ratios of the gels were Studied in detail. It is shown that both NaCl concentration and pH value of the buffer solution affect the swelling properties of the P(AA-co-AAEM) gels greatly. Moreover, the gel deswelling behavior induced by a direct current electric field was investigated and an excellent electric-sensitivity was found. Among all the samples, the gel with monomer feed weighty ratio (R) = 0.1479 showed the best electrical contraction properties. On the basis of the experimental results, the mechanism of the electricity-induced deswelling behavior was presented. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3690-3696, 2008