The effects of processing methods-free casting and spinning-on dispersion of nano-ZnO in a polyacrylonitrile (PAN) matrix were studied for this article. From observation with an transmission electron microscope, it was found that monoaxial drawing in spinning processing formed a fiberlike image of the nano-ZnO phase in the PAN matrix. The geometric parameters-the diameter and ratio of the nanoparticle phase-were about 20 and 15 nm, respectively, when the concentration of nano-ZnO was 1 wt % in the PAN matrix, whereas spherelike morphology was obtained by free casting, for which, naturally, the ratio of its length to its diameter was unity. This indicates that evidently the morphology of the nanoparticle phase is affected by processing methods. However, when the concentration of nano-ZnO went up to 2 wt % in the PAN matrix spinning process, the linear ratio of length to diameter of the nanoparticle phase decreased to 2.9 because drawing energy adsorption, through deformation of the nanoparticle phase, became a marked effect. The degree of anisotropy, including crystallization and orientation of polymer, was also affected by the concentration of nano-ZnO for the same reason. When the concentration of nano-ZnO reached 2 wt %, the anisotropy of PAN was obviously depressed according to the results of wide-angle X-ray measurement. (C) Wiley Periodicals, Inc.