In this paper, isotactic polystyrene (iPS) nanorods with gradient crystallite distribution were demonstrated. The polymer nanorods with a diameter of 65 nm were prepared by melt-wetting the nanoporous alumina template with fractionated iPS melts. Spatial distribution of crystallinity and orientation of the polymer in the nanorods from top to bottom were analyzed by Fourier transform infrared spectroscopy. The crystallites with perpendicular orientation (c-axis perpendicular to the long axis of rod) increased from the top to the bottom of the nanorods due to crystallization initiated by nuclei formed in the bulk and subsequent crystallite growth constrained by the nanopores. This result offers a unique approach to design polymeric nanomaterials with gradient crystallite distribution for functional nanodevice applications.
