Polyamide reverse osmosis (RO) membranes with carbon nanotubes (CNTs) are prepared by interfacial polymerization using trimesoyl chloride (TMC) solutions in n-hexane and aqueous solutions of m-phenylenediamine (MPD) containing functionalized CNTs. The functionalized CNTs are prepared by the reactions of pristine CNTs with acid mixture (sulfuric acid and nitric acid of 3:1 volume ratio) by varying amounts of acid, reaction temperature, and reaction time. CNTs prepared by an optimized reaction condition are found to be well-dispersed in the polyamide layer, which is confirmed from atomic force microscopy, scanning electron microscopy, and Raman spectroscopy studies. The polyamide RO membranes containing well-dispersed CNTs exhibit larger water flux values than polyamide membrane prepared without any CNTs, although the salt rejection values of these membranes are close. Furthermore, the durability and chemical resistance against NaCl solutions of the membranes containing CNTs are found to be improved compared with those of the membrane without CNTs. The high membrane performance (high water flux and salt rejection) and the improved stability of the polyamide membranes containing CNTs are ascribed to the hydrophobic nanochannels of CNTs and well-dispersed states in the polyamide layers formed through the interactions between CNTs and polyamide in the active layers.

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Biocidal poly(oxyethylene)s with N-halamine side groups were prepared using polymer analogous reactions of poly[oxy(chloromethyl)ethylene] with 5,5-dimethylhydantoin followed by chlorination. The biocidal poly(oxyethylene) films effectively inactivated the gram-negative bacteria Escherichia coli and maintained their biocidal property after long-term (3-month) storage. Since biocidal poly(oxyethylene) films have antibacterial efficacy and stability on hard surfaces, they could be useful in a variety of household and medical antibacterial applications.

We prepared polymeric N-halamine/silver nanoparticle composites to develop new effective biocidal systems. They were synthesized by mixing poly[oxy[(3-chloro-4,4-dimethyl-imidazolelidine-2,5-dionyl)methyl]ethylene](POCE) with silver perchlorate followed by UV reduction. These composites exhibit potent antibacterial activity against the gram-negative bacteria, Escherichia coli.

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