Role of gelator concentration in shaping the molecular and macroscopic properties of thymol:camphor supramolecular eutectogels

Monoterpenoid-based hydrophobic deep eutectic solvents (HDES) are attracting attention across various industrial sectors. A further advancement is their application as gel materials, known as eutectogels, which enable a broader range of task-specific applications. Here we report the straightforward preparation of hydrophobic eutectogels (HEGs) through the self-assembly of the low molecular weight gelator 1,3:2,4-dibenzylidene-D-sorbitol (DBS) within the thymol:camphor (Thy:Cam) HDES at 1:1 molar ratio. Recognizing that gelator concentration is crucial for tailoring the properties of the HEGs, five eutectogels were prepared with DBS concentrations ranging from 1 wt% to 10 wt%, forming sustainable gels in minutes. Comprehensive characterization at both molecular and macroscopic scales revealed a complex relationship between gelator content and the resulting material properties. All systems exhibit significant thermal stability, with degradation temperatures as high as 200 °C. Intermolecular interactions between HDES species and the DBS matrix, as well as possible microheterogeneities, were found to strongly influence the rheological and thermal behavior of the eutectogels, as well as the molecular mobility. Altogether, our results imply that HDES species experience multiple dynamic processes, underscoring the intricate interplay between the HDES components and the DBS matrix. This research highlights the critical role of gelator content in tuning the bulk and molecular physicochemical properties of Thy:Cam HEG and provides critical insights into the design of tailored gel materials. The findings emphasize the need for multiscale investigations to fully understand and optimize these materials, contributing to further advancements in innovative applications in material science, green chemistry, and biotechnology.