Electrospinning of chitosan nanofibers: The favorable effect of metal ions

This study is aimed to assess the doping effects of monovalent, bivalent, and trivalent metal ions on the morphological appearance of the electrospun chitosan/poly(ethylene oxide) (PEO) blend nanofibers. Scanning electron micrographs confirmed that the presence of 0.4-1.6 wt% NaCl (or KCl) in the blend solutions produced nanofibers, accompanying re-crystallization of inorganic salts, while addition of appropriate amounts of CaCl2 or FeCl3 (similar to 0.8 wt%) resulted in beneficial effect on defect-free nanofibers. The Fourier transform infrared spectra and rheological analysis results implied that the addition of metal ions were favorable for decreasing the viscosity (45-60%) and hydrogen bonds of the blends. Moreover, the fabrication of metal-ion-modulated chitosan/PEO nanofibers would lend experience to processing binary, ternary or multinary biologically active trace elements-codoped nanofibers via electrospinning. This general electrospinning strategy, which involves doping of metal ions, may be versatile to modulate the fibrous structure and functionality of polymers. (C) 2010 Elsevier Ltd. All rights reserved.