Polymer crystal nucleation with confinement-enhanced orientation dominating the formation of nanohybrid shish-kebabs with multiple shish

Abstract

Nanofillers with small lateral size can induce the formation of nanohybrid shish-kebab (NHSK) structures in polymer solution, which have a variety of potential applications. We performed dynamic Monte Carlo simulations to investigate polymer crystallization behaviors induced by aligned anisotropic filler networks. An unexpected NHSK structure with multiple shish is observed. The aligned fillers act as multiple shish and the polymer crystal lamellae form kebabs. Further detection reveals that crystal nucleation firstly occurs inside the filler networks due to the high polymer density and segmental orientation. Then, the nuclei grow to connect the fillers to finally form the NHSK structure with multiple shish. The presence of filler networks imposes confinement effects on the conformations and dimensions of chains inside, forces those chains to orient along the long axis of the fillers, reduces the conformational entropy, thus resulting in stronger nucleation ability of the chains inside. The nucleation mechanism can be also applied to interpret the formation process of the shish-kebab structure with multiple shish formed in sheared polymer melts, which was observed by Hsiao et al. (Phys. Rev. Lett. 2005, 94, 117802).