Microbial infection remains one of the most serious complications in several areas, particularly in medical devices, drugs, health care and hygienic applications, water purification systems, hospital and dental surgery equipment, textiles, food packaging, and food storage. Antimicrobials gain interest from both academic research and industry due to their potential to provide quality and safety benefits to many materials. However, low molecular weight antimicrobial agents suffer from many disadvantages, such as toxicity to the environment and short-term antimicrobial ability. To overcome problems associated with the low molecular weight antimicrobial agents, antimicrobial functional groups can be introduced into polymer molecules. The use of antimicrobial polymers offers promise for enhancing the efficacy of some existing antimicrobial agents and minimizing the environmental problems accompanying conventional antimicrobial agents by reducing the residual toxicity of the agents, increasing their efficiency and selectivity, and prolonging the lifetime of the antimicrobial agents. Research concerning the development of antimicrobial polymers represents a great a challenge for both the academic world and industry. This article reviews the state of the art of antimicrobial polymers primarily since the last comprehensive review by one of the authors in 1996. In particular, it discusses the requirements of antimicrobial polymers, factors affecting the antimicrobial activities, methods of synthesizing antimicrobial polymers, major fields of applications, and future and perspectives in the field of antimicrobial polymers.

Disinfecting, nonbleaching compound 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) was uniformly coated onto polypropylene melt-blown nonwoven fabrics having basis-weights of 22 and 50 g/m(2) in order to impart antimicrobial properties via a pad-dry technique. The antimicrobial efficacies of the tested fabrics loaded with MC compound were evaluated against bioaerosols of Staphylococcus aureus and Escherichia coli O157:H7 utilizing a colony counting method. It was determined that both types of coated fabrics exhibited superior antimicrobial efficacy upon exposure to aerosol generation for 3 h. The effect of the coating on air permeability was found to be minimal. Samples were stable for a 6 month time period when they were stored in darkness. However, when the fabrics were exposed to fluorescent light, partial chlorine loss was observed. The MC-coated fabrics exhibited great potential for use in protective face masks and air filters to combat airborne pathogens.

A series of new N-halamine epoxide precursors, 3-glycidyl-5,5-dialkylhydantoins (GH's), has been synthesized by a very facile and economic method. Cellulose surfaces can be treated with GH's and rendered biocidal by exposure to halogen solutions after curing the treated material. The biocidal efficacy tests showed that the chlorinated treated cellulose surfaces were antimicrobial with contact times required for 6-7 log reductions of Staphylococcus aureus and Escherichia coli O157:H7 of 5-30 min. It was found in simulated washing tests that celluloses, such as cotton swatches, treated with 3-glycidyl-5,5-dimethylhydantoin were quite stable and could survive more than the equivalent of 50 repeated home launderings with very little loss. Upon loss of the biocidal property due to long-term use, the treated surfaces could be recharged by further exposure to dilute bleach to regain antimicrobial activity. In addition, since only water was used as a solvent for the synthesis of GH's at room temperature, the reaction solution could be directly used as a treatment solution. Stability tests showed that the reaction solutions were relatively stable at room temperature and more stable at 5 °C over a period of at least 30 d. Preliminary experiments have shown that polyester swatches can also be treated with GH's and be rendered biocidal upon treatment with household bleach. The entire process should be economical for commercial application.