Understanding crystal orientation in quasi-one-dimensional polymer systems

We performed molecular simulations of polymer crystallization confined in rigid nanotubes. We found that the neutrally repulsive walls of nanotubes enhance the crystal nucleation. This enhancement gives uniform crystal orientation parallel to the tube axis at high temperatures. However, the nanotube walls that are wetted by the polymer, i.e. 'sticky' walls, switch the dominant crystal orientation from parallel to perpendicular. Since only perpendicularly oriented crystals can grow along the tube to give high crystallinities, the sticky walls provide a promising route towards the mass production of uniformly oriented nanocrystals in quasi-one-dimensional polymer systems.