Moebius strips of chiral block copolymers.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31501424.
- Also identified by DOI 10.1038/s41467-019-11991-3 and PMC identifier 6733789.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The Moebius topology (twisted, single-sided strip) is intriguing because of its structural elegance and distinct properties. Here we report the generation of block copolymer Moebius strips via a fast self-assembly of chiral block copolymer polystyrene-block-poly(D-lactide acid) (PS-b-PDLA) in tetrahydrofuran/water mixed solvents. The Moebius strip is formed by morphological evolution from large compound micelle (LCM) to spindle-like micelle (SLM) and then to toroid with a 180° twist along the ring. Mechanism insight reveals that a subtle balance of crystallization of PDLA and microphase separation between PS and PDLA chains dominates the formation of Moebius strips. An intriguing helix-helix transition occurs during the chiral transfer from microphase to assemblies, which is driven by relaxation of the internal stress within SLM related to orientated stretching of PS chains. Mesoporous chiral channels can be generated within Moebius strips after removal of PDLA, which are interesting in chiral recognition, separation and asymmetric catalysis.