Dual-Responsive Supramolecular Inclusion Complexes of Block Copolymer Poly(ethylene glycol)-block-Poly[(2-dimethylamino)ethyl methacrylate] with α-Cyclodextrin

A new class of temperature and pH dual-responsive and injectable supramolecular hydrogel was developed, which was formed from block copolymer poly(ethylene glycol)-block-Poly[(2-dimethylamino)ethyl methacrylate] (PEG-b-PDMAEMA) and a-cyclodextrin (alpha-CD) inclusion complexes (ICs). The PEG-b-PDMAEMA diblock copolymers with different ratio of ethylene glycol (EG) to (2-dimethylaminolethyl methacrylate (DMAEMA) (102:46 and 102:96, respectively) were prepared by atom transfer radical polymerization (ATRP). H-1 NMR measurement indicated that the ratio of EG unit to alpha-CD in the resulted ICs was higher than 2:1. Thermal analysis showed that thermal stability of ICs was improved. The rheology studies showed that the hydrogels were temperature and pH sensitive. Moreover, the hydrogels were thixotropic and reversible. The self-assembly morphologies of the ICs in different pH and ionic strength environment were studied by transmission electron microscopy. The formed biocompatible micelles have potential applications as biomedical and stimulus-responsive material. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2143-2153, 2010