Structural Organizations of a Mesogen-Terminated Semicrystalline Polymer: Chain Termini Ordering between Polymer Crystal Lamellae

Abstract

In polymer crystallization, the chain end groups are generally excluded into the nanoscaled amorphous regions confined between crystal lamellae. Understanding the structural characteristic and evolution of interlamellar end groups is of great importance to control the macroscopic properties of polymers. However, the structural evolution of those confined end groups and related physical evidence remain unclear. Herein, we synthesized the end-functionalized poly(lactic acid)s with a self-assemblable mesogenic termini (4-hexyloxy-4'-cyanobiphenyl) and investigated the structural evolution of mesogenic termini between crystal lamellae. Intriguingly, the mesogenic termini can organize into an ordered layer structure between polymer crystal lamellae; such a process strongly depends upon the interlamellar spacing. A higher crystallization temperature (Tc) of the polymer allows for a larger interlamellar region, favoring the formation of an ordered mesogenic layer. However, a lower Tc results in a restricted interlamellar region, in which the end groups are strongly confined without sufficient mobility to undergo structural ordering. This study provides evidence for the structural ordering of chain termini confined between polymer crystal lamellae.