Macroscopically anisotropic supramolecular materials prepared from an undercooled liquid-crystalline phase of a cholesterol-based low-molecular-weight compound

Abstract

Supramolecular bulk materials composed of low-molecular-weight compounds offer a promising pathway toward sustainable materials. However, achieving a macroscopic structural order and tuneable mechanical properties without relying on covalently bonded macromolecular components remains a significant challenge. We develop a supramolecular material derived from a cholesterol-based low-molecular-weight compound, (3β)-cholest-5-en-3-yl dodecylcarbamate, that forms a metastable liquid-crystalline (LC) phase upon quenching from its isotropic melt. The LC phase displays sufficient fluidity at room temperature to permit bulk processing, for example, by compression; the material subsequently undergoes spontaneous crystallization to form a self-standing sheet. By controlling the quenching temperature and the incubation time prior to processing, we succeed in endowing the sheet with molecular ordering that extends beyond the centimetre scale and, as a result, the sheet exhibits anisotropic mechanical properties. These findings establish a design strategy for creating processable, structurally tuneable, bulk materials exclusively from small molecules. Supramolecular bulk materials formed by low-molecular-weight systems offer a promising sustainability solution, but achieving order and tuneable properties is challenging. Here the authors develop a supramolecular cholesterol-based material that forms a metastable liquid crystalline phase upon quenching from its isotropic melt.