Electrospinning is a process of producing ultrafine fibers by overcoming the surface tension of a polymer solution with electrostatic force. In this study, iron acetylacetonate was added to a polyacrylonitrile solution, and the role of polymer-salt-solvent interactions in the electrospinning of the ultrafine fibers was investigated. The polymer-salt-solvent interactions were characterized by Fourier transform infrared spectroscopy; and the solution viscosity, conductivity and surface tension were measured in solutions with different salt concentrations. The formation of polymer-salt-solvent interactions increased the solution viscosity, conductivity, and surface tension values at low salt concentrations. At high concentrations, the solution viscosity and surface tension decreased, but the conductivity remained relatively constant. The polymer-salt-sol vent interactions influenced the structures of the electrospun fibers by changing the balance among the solution viscosity, conductivity, and surface tension. (C) 2008 Wiley Periodicals, Inc.