Fabrication and evaluation of electrospun nanofibrous antimicrobial nylon 6 membranes

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 electrospinning 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 γ form crystals (Tm ≈ 212 °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.