Surface contact disinfecting technique is a newly developed method for water sterilization.To prepare the antibacterial material having special ability and deeply study the antibacterial process and mechanism of surface contact disinfectant containing quaternary ammonium salts

the antibacterial and temperature responsive functional copolymer (poly(DMAE-BC-co-NIPAAm)) was introduced onto the surface of polyethylene (PE) films by UV-induced photografting method.IR showed that the copolymer of DMAE-BC and NIPAAm were successfully grafted onto the film.The surface of photo-grafted films was investigated through water contact angle (CA) measurements.It was found that the hydrophobicity of the co-grafted film increased with the temperature increasing from 20℃ to 40℃.The antibacterial properties of the co-grafted film were mainly investigated using -Escherichia coli (E.coli)

a kind of gramnegative bacteria

as model bacterium.First

the desorption of bacteria cells adsorbed on the surface co-grafted films was measured.In the 1 mol/L NaCl solution

lower than 35% bacteria cells was rinsed out from grafted films because the positive change on the antibacterial film surface was shielded

and the desorption rate of E.coli cells decreased with increasing temperature from 20℃ to 40℃.The cell-lysis action to bacteria cell was further investigated by measuring the activity of β-galactosidase.The antibacterial film was put into the cell suspension containing O-nitraphenyl β-D-galactopyranoside (ONPG)

and the changes of absorption at 400 nm with time were measured.The fact indicated that the co-grafted film disrupted the cell inner membrane

and the destroying action to the cell increased with increasing temperature from 20℃ to 40℃.The co-grafted film was believed to have both the antibacterial ability and temperature sensitivity

and the antibacterial ability changed with the temperature.The experimental results clearly showed the hydrophobic action played an important effect in both the desorption and cell-lysis steps.