# Enantiomeric Ratio Modulates Hierarchical Networks and Rheological Performance in Cyclohexane Bisurea Supramolecular Gels

## TL;DR

This paper shows how mixing left and right-handed molecules in specific ratios can create stronger and more efficient gels.

## Contribution

The novel approach uses enantiomeric ratios to design supramolecular gels with enhanced mechanical properties and ultralow gelation concentrations.

## Key findings

- Non-equimolar enantiomeric mixtures achieved a CGC of less than 2 mg/mL in toluene.
- Non-equimolar gels showed 17x higher yield stress and 20x higher storage modulus than single-enantiomer gels.
- Hierarchical 'sea urchin-like' structures formed from non-equimolar mixtures, enhancing network connectivity.

## Abstract

This study presents an enantiomeric-ratio-driven strategy for constructing mechanically robust supramolecular gels using cyclohexane bisurea derivatives. By employing non-equimolar enantiomeric mixtures, we achieved an ultralow critical gelation concentration (CGC < 2 mg/mL) in toluene, representing a reduction of more than fivefold compared to homochiral single-enantiomer systems. Rheological measurements revealed substantially enhanced mechanical properties in the non-equimolar gels, with yield stress and storage modulus values up to 17 and 20 times higher, respectively, than those of single-enantiomer gels. Morphological analyses (SEM and POM) indicated that pure enantiomers form isolated crystalline fibers with limited connectivity, whereas racemic mixtures yield disordered amorphous aggregates. In contrast, non-equimolar mixtures self-assemble into hierarchical “sea urchin-like” architectures, wherein crystalline fibers radiate from central cores to form densely interconnected networks. This unique structural motif underpins both the ultralow CGC and superior mechanical performance. Complementary FT-IR, XRD, and DSC analyses demonstrated that chiral imbalance modulates hydrogen-bonding interactions and structural order, while molecular dynamics (MD) simulations provided insight into the divergent self-assembly pathways among homochiral, racemic, and non-equimolar systems. This work provides a stereochemically guided approach for designing high-performance supramolecular gels with tailored hierarchical structures and enhanced functionality.