Unveiling the secrets of unusual long-pitch periodic assembly of poly(ʟ-Lactide) ring-banded spherulites

Abstract

Although polymer physicists have conducted extensive research over the decades, the molecular assembly in lamellae of ring-banded spherulites (RBS) remains a puzzle that has yet to be solved. Nonetheless, a breakthrough has occurred in this field where long-pitch banded rings made of a model poly(ʟ-lactide) (PLLA) were examined using advanced synchrotron X-ray micro-focused diffraction techniques. Through the microbeam diffraction mapping and microscopy 3D dissection morphology, the periodic banded structure of RBS is composed of lamellae that self-assemble as structural gratings. Furthermore, a comparison of optical micrograph image with the mapping results revealed the sequential arrangement and orientation of lamellae in these gratings. These extensive experimental findings now provide a comprehensive and novel explanation for the formation of long-pitch lamellar assembly in RBS. This new methodology is adaptable to a wide variety of polymers and allows for the analysis of spherulites displaying periodically self-assembled patterns. The novel methodology employed here has a versatile applicability for a diverse range of polymers. This technique can be extended to analyze spherulites showcasing periodically self-assembled patterns. Such revelation provides valuable understanding into the complex structures and behaviors of polymers, and this discovery opens up new frontiers in materials science research and its practical applications.