Suppression of the Self-Nucleation Effect of Semicrystalline Polymers by Confinement

Abstract

The melt memory effect is well-known in polymer crystallization. It is caused by self-nuclei that persist above the melting temperature. The origin and physical nature of self-nuclei are still under debate. In this work, we studied the effect of confinement on the self-nucleation behavior of two typical semicrystalline polymers: poly(ε-caprolactone) (PCL) and poly(butylene succinate) (PBS) using anodic aluminum oxide (AAO) templates. The density of AAO nanopores covers a range of 1011 ~ 1013 cm-3. Narrowing of the self-nucleation region (Domain II) with a decrease of AAO diameter was observed for both infiltrated PCL and PBS, indicating the suppression of the self-nucleation effect. When the diameter of AAO is below 60 nm, Domain II vanished. Further analysis indicated that Domain IIa (melt memory region) vanished first, followed by Domain IIb (self-seeding region). The results provide a method of estimating the self-nuclei density of different polymers at different temperatures.