The Preparation And Characterization Of Dual Stimuli Responsive Supramolecular Hydrogels And Microgels

Stimuli-responsive hydrogels and microgels which can response to external stimulis,such as temperature,pH and light have great potential to be used as self-healing materials,microreactors and biomedical materials.This paper focused on dual stimuli-responsive hydrogels and microgels,and the results were as follows:(1)A series of copolymers were synthesized by poly(N-isopropylacrylamide)and 2,6-bis(N-methylbenzimidazolyl)pyridine(BIP).And metallo-microgels were successfully prepared through metal-ligand bond between BIP lignd and metal ions in organic solution.The microgels were proved to possess metal ions responsibility.(2)A triblock copolymer PNIPAM-b-PMAABIP-b-PNIPAM was prepared and temperature and metal ions dual stimuli-responsive microgels were prepared in water.The PNIPAM chain would collapse and lead to the decrease of the size of the microgels when temperature raised to the lower critical solution temperature(LCST).Also,the metal-ligand bond would be broken and caused the enhancement of the fluorescence intensity when temperature raised.(3)A series of pH-temperature dual stimuli-responsive random copolymers were prepared by poly(N,N-dimethylaminoethyl methacrylate)(PDMAEMA)and poly(ethylene glycol)methyl ether methacrylate)(PMPEGMA)).And supramolecular hydrogels were prepared through host-guest interactions between?-cyclodextrin(?-CD)and poly(ethylene glycol).The drug release behavior of the supramolecular hydrogels was studied.The release of model drug could be effectively controlled by altering the temperature and pH values.The supramolecular hydrogels had good release property at 37 and 45 oC,and the release time could reach to 20 hours under both acidic and neutral conditions.