Formation mechanism of reverse kebab structure inside hollow nanotubes studied by molecular simulations

Abstract

Formation of polymer crystals inside a hollow nanotube provides the potential for its interior functionalization. Based on dynamic Monte Carlo simulations, the formation mechanism of crystal lamellae with uniform orientation inside hollow nanotubes in polymer solutions was investigated. In nanotubes with lateral size smaller than the size of chain coils, inside segments prefer to orient along the long axis of the nanotubes, due to the confinement effect exerted by side surfaces. Thus, crystal lamellae with uniform orientation along the long axis of the nanotubes can be formed inside. Further investigations revealed that the formation of these reverse kebabs is codetermined by the degree of confinement and the strength of interfacial interaction. Both the increase of interfacial interaction and the decrease of lateral size can lead to the improvement of segmental orientation of inside segments, thus favoring the formation of the reverse kebabs.