Thermodynamic and mechanical properties of supramolecular gel based on bisterpyridine ligand formed via a cooperative model

Abstract

Supramolecular gels hold immense potential in materials science, particularly in the development of functional materials for optoelectronics, sensors, and soft robotics. Their tunable mechanical properties and hierarchical self-assembly facilitate precise control over material structures and functions. Herein, we present a comprehensive study of the photophysical and mechanical properties of a supramolecular gel derived from a bisterpyridine ligand. The bisterpyridine ligand 1, incorporating alanine moieties as chiral units, was successfully synthesized. Notably, 1 exhibited gelation in aromatic solvents such as toluene and xylene, forming a supramolecular gel with a distinctive twisted fiber morphology. The heating and cooling curves exhibited non-sigmoidal shapes, indicating that supramolecular gel 1 prepared in toluene, was formed via a cooperative mechanism. The Gibbs free energy was calculated to be −32.82 kcal mol⁻¹. Furthermore, supramolecular gel 1 displayed strong blue emission, highlighting its potential for optoelectronic applications. The mechanical properties of 1 were investigated via rheometry, revealing a pronounced thixotropic behavior, indicative of a reversible gelation process. These findings underscore the adaptability and multifunctionality of supramolecular gel 1, making it a promising candidate for advanced material applications.