Mapping the local ambidextrous chirality in thin films of NTB phase by circular dichroism spectra

Yu, Huanan; Welch, Chris; Mehl, Georg H.

Abstract

Circular dichroism mapping (CDM) method was introduced by utilizing the highly collimated light beam of synchrotron radiation (SR) available at Diamond Light Source B23 beamline for scanning the thin films of the NTB phase. We apply SR-CDM to two achiral dimeric materials exhibiting the NTB phase: symmetric DTC5C9 and dissymmetric DTC5C9CB. The SR-CDM measurements directly capture the chiral information in the local NTB domains, providing the ultimate complement to the theoretical predictions of the helical structures: the spontaneous symmetry breaking in NTB phase is ambidextrous. The macroscopic chirality of the NTB phase is determined by the combination of doubly degenerate locally chiral domains in the illuminated area. Additionally, we investigate the temperature dependence, as well as the dynamic nature of the local chirality in the NTB phase by in-situ SR-CDM, confirming a chiral conversion influenced by the state of enantiomeric aggregation and a progressive unwinding of the helical structure in left-handed domains as the crystallization temperature is approached.

Citation

Yu, H., Welch, C., & Mehl, G. H. (2025). Mapping the local ambidextrous chirality in thin films of NTB phase by circular dichroism spectra. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 330, Article 125682. https://doi.org/10.1016/j.saa.2024.125682

• Journal Article Type: Article
• Acceptance Date: Dec 26, 2024
• Online Publication Date: Dec 27, 2024
• Publication Date: 2025-04
• Deposit Date: Feb 12, 2025
• Publicly Available Date: Dec 28, 2025
• Print ISSN: 1386-1425
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 330
• Article Number: 125682
• DOI: https://doi.org/10.1016/j.saa.2024.125682
• Public URL: https://hull-repository.worktribe.com/output/5003246