Injectable supramolecular hybrid hydrogels formed by MWNT-grafted-poly(ethylene glycol) and α-cyclodextrin

Poly(ethylene glycol)- grafted -multiwalled carbon nanotube (MWNT- g- PEG) was synthesized by a coupling reaction and formed inclusion complexes (ICs) after selective threading of the PEG segment of the MWNT- g- PEG through the cavities of α-cyclodextrins (α-CDs) units. The polypseudorotaxane structures of the as-obtained hydrogels were confirmed by 1 H NMR, X-ray diffraction and DSC analyses. The complexation of the PEG segments with α-CDs and the hydrophobic interaction between the MWNT resulted in the formation of supramolecular hybrid hydrogels with a strong network. Thermal analysis showed that the thermal stability of the hydrogel was substantially improved by up to 100 °C higher than that of native hydrogel. The resultant hybrid hydrogels were found to be thixotropic and reversible, and could be applied as a promising injectable drug delivery system. The mechanical strength of the hybrid hydrogels was greatly improved in comparison with that of the corresponding native hydrogels. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3145–3151, 2010