A fluorescent
solid-like giant vesicle was prepared by using an
anionic dye methyl orange (MO) and an oppositely charged surfactant
1-tetradecyl-3-methylimidazolium bromide (C14mimBr) on the basis of the ionic self-assembly (ISA) strategy.
The properties of MO/C14mimBr complexes were
comprehensively characterized. The results indicated that the giant
vesicle was formed by the fusion of small vesicles and could keep
its original structure during the evaporation of solvent. Besides,
the giant vesicles exhibit luminescent property owing to the break
of intermolecular π–π stacking of MO, which achieves
the transformation from aggregation-caused quenching to aggregation-induced
emission by noncovalent interaction. Moreover, MO/C14mimBr complexes also exhibit smart pH-responsive characteristics
and abundant thermic phase behavior. That is, various fluorescent
structures (polyhedron, giant vesicle, chrysanthemum, peony-like structure)
were obtained when pH ≥ 4, whereas a simple nonfluorescent
structure (microflake) was obtained when pH = 2 due to the changes
of MO configuration. Thus, the fluorescence behavior can be predicted
with the color change directly visible to the naked eye by changing
the pH. It is expected that the facile and innovative design of supramolecular
material by the ISA strategy could be used as pH detection probes
and microreactors.
Supramolecular hydrogels were prepared using a-cyclodextrin (a-CD) and a poloxamine (reverse Tetronic 90R4, T90R4) which has four diblock arms with a poly(propylene oxide)-poly(ethylene oxide) (PPO-PEO) structure. The a-CD can slide past the PPO blocks and towards the middle PEO blocks owing to the unsuitable energy between a-CD and PPO to form a-CD/T90R4 inclusion complexes (ICs). The incorporation of graphene oxide (GO) into a-CD/T90R4 ICs changes their phase behavior and forms mechanically strong hydrogels because of the hydrogen-bonding between the GO nanosheets and the a-CD and PEO blocks of T90R4. The native hydrogel, as well as the a-CD/T90R4/GO hybrid hydrogels, have been thoroughly characterized by using various microscopy techniques. Field emission scanning electron microscopy (FE-SEM) was used to observe the morphology of the hydrogel, and differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to evaluate the thermal stability of the hydrogel. Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) were used to characterize the interactions within the supramolecular assemblies and the degree of crystallinity of the xerogels, respectively. The experimental results demonstrated that a-CD/T90R4/GO hybrid hydrogels could adsorb various dyes selectively, and that it is a promising candidate for sewage treatment, while the native one cannot adsorb the dyes well. Moreover, the native a-CD/T90R4 hydrogel has excellent biocompatibility, and the results of the in vitro drug release study showed that the injectable doxorubicin (DOX)-loaded hydrogel is appropriate for the controlled release of anticancer drugs, while the a-CD/T90R4/GO hybrid hydrogels can reduce the release rate of DOX.
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