Smart supramolecular hydrogels have been prepared from a bolaamphiphilic L‐valine derivative in aqueous solutions of different salts. The hydrogels respond selectively to different ions and are either reinforced or weakened. In one case, in contrast to conventional systems, the hydrogels are formed upon heating of the system. The use of the hydrogels in the controlled release of an entrapped dye is described as a proof of the potential applications of these systems. The responsive hydrogels were rationally designed by taking into account the noticeable effect of different ions from the Hofmeister series in the solubility of the hydrogelator, which was assessed by using NMR experiments. On the one hand, kosmotropic anions such as sulfate produce a remarkable solubility decrease in the gelator, which is associated with gel reinforcement, as measured by rheological experiments. On the other hand, chaotropic species such as perchlorate weaken the gel. A dramatic effect was observed in the presence of guanidinium chloride, which boosted the solubility of the gelator, in accordance with its chaotropic behaviour reported in protein science. In this case, a direct interaction of the guanidinium species with the carbonyl groups of the hydrogelator is detected by 13C NMR spectroscopy. The weakening of this interaction upon a temperature increase allows for the preparation of heat‐set hydrogelating systems.

Dedication ((optional))Efficiency of molecular gel formation of simple derivatives from L-valine and L-isoleucine is much improved in different organic solvents when replacing a hexyl fragment by a bulkier cyclohexyl one. A study using NMR and IR provides information on the preferred conformations of the molecules indicating that the cyclohexyl moiety precludes intramolecular H-bonding and preorganises the system for intermolecular interactions responsible for fiber formation. NMR data of the gels provide thermodynamic data for fibrillization revealing that the origin of this effect is mainly entropic. Electron microscopy (SEM and TEM) images show fibrillar and tape-like objects observed commonly in molecular gels. Rheological measurements reveal significant differences between cyclohexyl and hexyl appended gelators. The conclusions reached could contribute to the rational design of small, flexible, building blocks for selfassembly.

A new molecular hydrogelator consisting of a L‐Valine derivative with appended quinoline units behaves as a supramolecular superhydrogelator forming gels at such low concentrations as 0.8 mM (0.05% w/w). On the other hand, an analogue compound containing a pyridine moiety is found to be a poor gelator, forming gels at 19 mM. The gels are pH sensitive because of the protonation of the heterocycle and show microcrystallinity. The rheological properties and biocompatibility are also reported.