Translational Dynamics and Structural Enhancement Effect in High-Temperature Supramolecular Systems of Asparaginyl Low-Molecular-Weight Gelators and Propylene Carbonate.

Chemical engineering paves the way for the design of new materials with targeted properties. Supramolecular chemistry allows the creation of molecular assemblies from small molecules based on noncovalent interactions between the components, e.g., hydrogen bonds and dispersive or electrostatic forces, leading to the templating of self-assembly structures. The reversible bonding interaction allows for optimization of the final structure and enhancement of the properties. In this study, we have used this approach to design and prepare supramolecular membranes that work at temperatures exceeding the 100 °C limit. The system is based on low molecular weight gelators (LMWGs), which provide versatility of compositions, flexibility, tunable properties, and improved sustainability. LMWG-based systems mostly exhibit gel-like features, offering an alternative with enhanced responsiveness, self-healing abilities, recyclability, and viscoelastic properties. In this context, we developed a gel-like membrane using an aspartame derivative as the LMWG and propylene carbonate as a liquid phase to prepare systems that can solidify carbonate solvents widely used in the chemical industry. The TGA/DTG and DSC thermal analyses were used to evaluate the system's performance at high temperatures. The intermolecular interactions, gelation mechanism, and solvent dynamics were examined using different nuclear magnetic resonance methods. The microstructures of the obtained membranes were studied by using a fluorescence confocal scanning microscope. The obtained results have shown that the designed systems subjected to proper thermal processing routes can achieve enhanced structural stability, allowing them to work continuously at temperatures exceeding the 100 °C limit. The NMR studies showed that translational dynamics of the solidified liquid remain comparable to those observed for the liquid state, preventing the bulk flow simultaneously and compensating for the thermal convection effects. The performed matrix analysis showed how the self-assembled supramolecular aggregates of the gelator evolve with the membrane composition. We have demonstrated that the investigated membranes exhibit efficient self-healing effects above some concentration threshold.