The bactericidal monomer 2,4,4'-trichloro-2'-acryloyloxydiphenyl ether (AcDP) was synthesized from 2,4,4'-trichloro-2'-hydroxydi-phenyl ether (DP) and acryloyl chloride in the presence of triethylamine in dry THF at 20 degrees C. The synthesized AcDP was identified by IR, H-1-NMR, and GC-MS spectra. The homopolymers of AcDP were obtained using benzoyl peroxide as a thermal initiator in toluene under different experimental conditions such as various initiator concentrations, polymerization temperatures, and polymerization times. The copolymer of AcDP and methyl methacrylate (MMA) was synthesized with a thermal initiator. Poly(AcDP) and poly(AcDP-co-MMA) were identified by LR. and H-1-NMR spectra. The maximum weight-average molecular weights (($) over bar M(w)) of poly(AcDP)s and poly(AcDP-co-MMA)s were 6,700 and 15,600, respectively. The monomer reactivity ratios, r(1) (AcDP) and r(2) (MMA), determined by the Kelen-Tudos method, were 0.26 and 1.12, respectively. The glass transition temperature and the decomposition temperature of poly(AcDP) were 73.4 and 348 degrees C, respectively. The bactericidal activities of AcDP, poly(AcDP), and poly(AcDP-co-MMA) were studied using the agar dish test. The bactericidal activities of AcDP and its polymers as well as DP against Pseudomonas aeruginosa were very excellent compared to those of such control polymers as poly(MMA) and poly( ethylene-co-vinyl acetate). The bactericidal activities decreased in the order DP > AcDP > poly(AcDP) > poly(AcDP-co-MMA) against P aeruginosa.