Unprecedented cubic mesomorphic behaviour of crown-ether functionalized amphiphilic cyclodextrins

• Published in: Chemistry : a European journal p. e202403232
• Main Authors: Espejo, Jayar, Zellmann-Parrotta, Carson O, Sarkar, Diganta, Che, Austin, Michaelis, Vladimir K, Williams, Vance E, Ling, Chang-Chun
• Format: Journal Article
• Language: English
• Published: Germany 09.10.2024
• Subjects: Crown ether cyclodextrin liquid crystal oligoethylene glycols bicontinuous cubic mesophase lithium conduction
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.202403232

Amphiphilic supramolecular materials based on biodegradable cyclodextrins (CDs) have been known to self-assemble into different types of thermotropic liquid crystals, including smectic and hexagonal columnar mesophases. Previous studies on amphiphilic CDs bearing 14 aliphatic chains at the primary face and 7 oligoethylene glycol (OEG) chains at the secondary face showed that the stability of the mesophase can be rationally tuned through implemation of terminal functional groups to the OEG chains. Here, we report the syntheses of first examples of crown ether-functionalized amphiphilic cyclodextrins that unexpectedly form thermotropic bicontinuous cubic phases. This constitutes the first reported examples of cyclodextrins forming such phases, which are potentially capable of 3D ion transport. Lithium composites were made to assess lithium conduction in the material. XRD revealed the added lithium salt destabilizes the cubic phase in favour of the smectic phase. Solid-state NMR studies showed that these materials conduct lithium ions with a very low activation energy.