The EPR magnetic susceptibility behavior of the camphorsulfonic acid doped polyaniline (PANCSA) blends with polyethylene oxide (PEO) is reported in fibers and films. In particular, EPR investigations on electrospun (PANCSA)(0.72)(PEO)(0.28) nanofibers, cast films of (PANCSA)(0.72)(PEO)(0.28) and cast films of (PANCSA) were performed to investigate differences in the mesoscopic disorder as induced by the process of electrospinning. The changes observed in the Pauli susceptibility, EPR lineshape, EPR linewidth, and de conductivity are interpreted as due to increased chain alignment in the fibers compared with the cast films. (C) 2003 Elsevier B.V. All rights reserved.