The preparation and characterization of electrospun polyacrylonitrile (PAN)/platinum(II) acetylacetonate composite nanofibers were investigated. The solution properties, such as viscosity, surface tension, and conductivity, of Pt-acetylacetonate-added PAN solutions in N,N-dimethylformamtide were measured, and their influences on the resulting fiber structure were also determined. At low Pt salt concentrations, the addition of Pt salt increased the fiber diameter but did not change the fiber diameter distribution. However, the fiber diameter decreased, and the fiber diameter distribution became broader when the Pt salt concentration went beyond a critical value. The structure of the electrospun fibers was determined by the formation of polymer-salt-solvent interactions, which changed the balance among the viscosity, surface tension, and conductivity of the solutions. (C) 2009 Wiley Periodicals, Inc.J Appl Polym Sci 116: 895-901, 2010