Aligning stem orientation: confined chiral and epitaxial growth of the α-phase crystals of isotactic polypropylene

In the past, soft materials under soft or hard confinement have been extensively studied due to size effect at a small scale. Polymer nanorods confined to the anodic aluminum oxide (AAO) template have been examined in terms of crystal nucleation and orientation. So far, few molecular studies have been done on the polymer nanostructure under cylindrical confinement. In this research, we have fabricated isotactic polypropylene (i-PP) into a rod-shaped nanomaterial. We carried out 2D wide-angle x-ray diffraction (WAXD) and electron diffraction (ED) experiments of transmission electron microscopy (TEM) to analyze the chiral and epitaxial growth effect on hierarchical structure of i-PP nanorod. We found that stems of mother lamellae prefer to align with the rod long-axis (nanopore axis of AAO) and stems of daughter lamellar tilt 100 degree clockwise or counterclockwise with respect to the rod long-axis under 2D confinement.