To achieve antimicrobial properties, three structurally different N-halamine additives, chlorinated 5,5-dimethylhydantoin (CDMH), chlorinated 2,2,5,5-tetramethyl-imidozalidin-4-one (CTMIO) and chlorinated 3-dodecyl-5,5-dimethylhydantoin (CDDMH), were introduced into the electro-spinning dope of nylon 6. Effects of N-halamine addition on the properties of electrospun nanofibrous membranes were investigated. Nuclear magnetic resonance (NMR) and attenuated total reflectance mode Fourier transform infrared spectroscopy (ATR-FTIR) were used to identify the synthesized N-halamine structures. Differential scanning calorimetry (DSC) and wide angle X-ray diffraction (XRD) revealed that the fraction of -gamma form crystals (T-m approximate to 212 degrees C) increased with the increase in the N-halamine content. Energy dispersive X-ray (EDX) mapping patterns confirmed the uniform distribution of N-halamines on the membrane surface. A total reduction of both Escherichia coli (gram-negative bacteria) and Staphylococcus aureus (gram-positive bacteria) was observed after a short contact period of 5-40 min based upon the type of N-halamine and the active chlorine contents. No significant leaching of N-halamine additives from electrospun nylon 6 membranes was observed. (c) 2007 Elsevier B.V. All rights reserved.