Poly(acrylic acid) (PAA) nanofibers were fabricated by electrospinning into NaCl solution. The effect of the ionic strength of NaCl on the morphology of PAA nanofibers was investigated. The smallest diameter of the PAA nanofiber was prepared with 0.01 M NaCl PAA solutions. At the concentration 1 M NaCl, PAA nanofibers could not be fabricated. The viscosity and conductivity changes were measured with changing the concentration of NaCl. It is suggested that diameter variations may be caused by conductivity and polymer chain conformation changes with varying the concentration of NaCl. (C) 2004 Elsevier B.V. All rights reserved.