Supramolecular hydrogels hybridized with single-walled carbon nanotubes

In this study, well-dispersed single-walled carbon nanotubes (SWNTs) were successfully incorporated into a supramolecular hydrogel through combining dual roles of Pluronic copolymer in dispersing SWNTs and forming inclusion complexes with alpha-cyclodextrin (alpha-CD). Such hydrogel hybridized with SWNTs was prepared by mixing an aqueous solution of alpha-CD with an aqueous dispersion of SWNTs stabilized by Pluronic copolymer. The structure and properties of the supramolecular hydrogels were studied in detail by means of a variety of characterization methods. The results obtained from X-ray diffraction (XRD), Raman spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) showed that the introduction of well-dispersed SWNTs had no obvious influence on the structure and morphology but changed the gelation mechanism comparing with that of the native hydrogel. The resultant hybrid hydrogel retained the basic characters of supramolecular hydrogel, especially the shear-thinning and reversible temperature-responsive properties. It is noteworthy that the introduction of SWNTs accelerated the gel formation obviously, but the ultimate strength of the hybrid hydrogels, characterized by viscosities and storage modulus, declined with the increase of SWNTs.