An instant-formative heat-set organogel induced by small organic molecules at a high temperature

This paper describes an instant-formative organogel triggered by small organic molecules (cogelators) at a high temperature. The system was prepared by beta-cyclodextrin (beta-CD) and lithium chloride (LiCl) in N, N-dimethyl acetamide (DMAc). Under stirring, a clear solution is obtained at 120-130 degrees C and transformed into a gel phase within several seconds once the cogelators are injected. The gelling times (GT) distribution of more than 1 min to no more than 1 s, which can be mediated by the concentration of cogelators. When beyond the certain concentration, cogelators can gel the system instantly which GT even cannot be precisely observed (below 1 s). Numerous kinds of short alkyl chain aliphatic molecules were studied as cogelators for the first time, which cover a broad range including acid, ketone, alcohol etc. Scanning electron microscopy (SEM) measurements revealed that the three-dimensional micromorphology were diverse corresponding to different functional groups of cogelators. The X-ray diffraction (XRD) measurement proves that the self-assembled mode of gel was head-to-head channel-type. Fourier transform infrared spectroscopy (FT-IR) measurement evidences the formation of intermolecular hydrogen bonds. The molecular dynamics simulation was performed to obtain the mechanism of the formation of the gel, and the result is consistent with the experimental phenomenon. We believe the specific properties of the gel may bring up a novel application of the supramolecular gel. (C) 2013 Elsevier B.V. All rights reserved.