Formation of heat-triggered supramolecular organogel in which β-cyciodextrin as sole gelator

摘要

β-Cyclodextrins (β-CDs), without the help of the guest molecules embedding in cavities, can self-assemble an organogel with a very small amount of lithium chloride (LiCl) in N,N-dimethylformamide (DMF). Microstructures of the organogel were confirmed to be β-CD molecular clusters composed of many channel-type β-CD fibers extending from a cage-type β-CD core in various directions. The process of the gel formation and the structure were suggested based on FTIR, TR-FTIR, 1H NMR and XRD results. The interactions of the various molecules in the system were discussed for gelation. The morphology of the organogel was characterized by OM and SEM. A molecular dynamics simulation of the gel structure was performed in agreement with the results. In addition, the concentration of β-CD for the gel formation ranged from 0.13 to 0.28mol/L. The approximate heat effect of the phase transition was 28 kJ/mol. This investigation will be of great significance to develop new temperature-controlling materials with native β-CD of low cost in application.