Stimuli-responsive supramolecular organogels that exhibit a succession of micro-morphologies

A novel supramolecular organogel consisting of β-cyclodextrin (β-CD), 4,4′-isopropylidendiphenol (BPA), LiCl, N,N-dimethylformamide (DMF) and ethanol (EtOH) was prepared. The system without EtOH was a clear solution at ambient temperature and turned into an organogel upon the addition of ethanol (EtOH). The micro-morphologies of the organogel were various, such as ellipsoids, spheres, cuboids and cylinders, and they could be obtained in sequence by controlling the stirring time or the dosage of introduced EtOH. The organogel with multi-morphologies was characterized by optical microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and rheology measurements. Further, the formation mechanism of the organogel was proposed. This organogel may cast new light on the area of functional material design and fabrication.

Optical microscope images of the organogel stirred for different times: A, ellipsoids, stirred for 7 min; B, spheres, stirred for 9 min; C, cuboids stirred for 11 min, D, larger cuboids, stirred for 13 min; and E, cylinders, stirred for 70 min; solution: Cβ-CD 0.167 mol/L, CBPA 0.167 mol/L, ωLiCl 0.5%; solution:ethanol = 1:1 (v/v) (scale bar = 1 μm in A–E). We found a novel organogel induced by ethanol. The micro-morphologies of this organogel were various and could be tuned by controlling the stirring time or the dosage of introduced ethanol.Figure optionsDownload as PowerPoint slideHighlights
► A novel supramolecular organogel was prepared.
► It was induced by ethanol.
► The morphologies of this organogel were various.
► The morphologies could be obtained by tuning ethanol dosage or stirring time.
► The organogel can trap a large amount of ethanol.