Rapid Phase Transitions of Thermotropic Glycolipid Quasicrystal and Frank-Kasper Mesophases: A Mechanistic Rosetta Stone

Angew Chem Int Ed Engl. 2023 Jun 5;62(23):e202302739. doi: 10.1002/anie.202302739. Epub 2023 May 2.

Abstract

Experimental results are presented that serve to lower the barrier for developing the science and technology of non-classical thermotropic glycolipid mesophases, which now include dodecagonal quasicrystal (DDQC) and Frank-Kasper (FK) A15 and σ mesophases that can be produced under mild conditions from a versatile class of sugar-polyolefin conjugates. By employing "alloys" comprised of mono- and disaccharide-polyolefin conjugates, and optionally with vitamin E as a small molecule phase modulator, we report the spontaneous formation of stable A15 mesophases at ambient temperature. We further document a rich thermotropic phase map that includes DDQC, A15, and σ mesophases of tunable periodicity that are connected through rapid thermotropic phase transitions as a function of increasing temperature in the order: liquid-like packing (LLP)→DDQC → A15→σ→ disorder. This first direct observation of a rapid thermotropic A15→σ phase transition provides support for a diffusionless martensitic process proceeding through strain-induced introduction of planar defects into the A15 lattice.

Keywords: Frank-Kasper; Glycolipid; Mesophase; Quasicrystal.