摘要
Copolymers of quaternary ammonium monomer（QAM） and hydrophilic co-monomer were successfully synthesized by free radical polymerization. It was discovered that the hydrophilic co-monomers with poor antibac- terial activity significantly enhanced the activity of QAM substituted with a long alkyl chain[i.e., N,N-dimethyl-N-dodecyl methacrylate ammonium bromide（DMAEMA-DB）]. When a suitable molar ratio of DMAEMA-DB to co-monomer was selected, the activity of the copolymers was up to 123 times that of the homopolymer of DMAEMA-DB against S. aureus, and 282 times that of it against E. colt. But unlike DMAEMA-DB, the co-monomers might weaken the activity of QAM substituted with a short alkyl chain[i.e., N,N-dimethyl-N-butyl methacrylate ammonium bromide（DMAEMA-BB）]. Moreover, it was found that copolymers of DMAEMA-DB were much more biocidal than those of DMAEMA-BB. Therefore, it could be speculated that the long alkyl chain plays an important role in the antibacterial activity, and that the hydrophilie co-monomers are beneficial to polymeric guaternary ammonium compounds（PQACs） to exert the positive effect of the long alkyl chain to the greatest degree.
Copolymers of quaternary ammonium monomer（QAM） and hydrophilic co-monomer were successfully synthesized by free radical polymerization. It was discovered that the hydrophilic co-monomers with poor antibac- terial activity significantly enhanced the activity of QAM substituted with a long alkyl chain[i.e., N,N-dimethyl-N-dodecyl methacrylate ammonium bromide（DMAEMA-DB）]. When a suitable molar ratio of DMAEMA-DB to co-monomer was selected, the activity of the copolymers was up to 123 times that of the homopolymer of DMAEMA-DB against S. aureus, and 282 times that of it against E. colt. But unlike DMAEMA-DB, the co-monomers might weaken the activity of QAM substituted with a short alkyl chain[i.e., N,N-dimethyl-N-butyl methacrylate ammonium bromide（DMAEMA-BB）]. Moreover, it was found that copolymers of DMAEMA-DB were much more biocidal than those of DMAEMA-BB. Therefore, it could be speculated that the long alkyl chain plays an important role in the antibacterial activity, and that the hydrophilie co-monomers are beneficial to polymeric guaternary ammonium compounds（PQACs） to exert the positive effect of the long alkyl chain to the greatest degree.
基金
Supported by the National Natural Science Foundation of China（No.50673101）, the Scientific Foundation of Guangdong Province of China（Nos.0711020600015, 2004A30404001）, the Natural Science Foundation of Guangxi Zhuang Autonomous Region of China（Nos.2013GXNSFBA019040, 2013GXNSFBA019036）, the Projcet of Department of Education of Guangxi Zhuang Autonomous Region, China（No.2013YB171） and the Foundation of Guangxi University of Science and Technology, China.
