Scrolling in Supramolecular Gels: A Designer’s Guide

• Published in: Chemistry of materials Vol. 36; no. 6; pp. 2799 - 2809
• Main Authors: Jones, Christopher D., Kershaw Cook, Laurence J., Slater, Anna G., Yufit, Dmitry S., Steed, Jonathan W.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26-03-2024
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.3c03013

Gelation by small molecules is a topic of enormous importance in catalysis, nanomaterials, drug delivery, and pharmaceutical crystallization. The mechanism by which gelators self-organize into a fibrous gel network is poorly understood. Herein, we describe the crystal structures and gelation properties of a library of bis­(urea) compounds and show, via molecular dynamics simulations, how gelator aggregation progresses from a continuous pattern of supramolecular motifs to a homogeneous fiber network. Our model suggests that lamellae with asymmetric surfaces scroll into uniform unbranched fibrils, while sheets with symmetric surfaces undergo stacking to form crystals. The self-assembly of asymmetric lamellae is associated with specific molecular features, such as the presence of narrow and flexible end groups with high packing densities, and likely represents a general mechanism for the formation of small-molecule gels.