Smart Microgel Particles with Tuneable Responses

Colloidal microgels that are able to alter their §volume and properties in response to environmental §stimuli are attractive materials for various §applications. However, current methods to prepare §microgels that possess both pH- and temperature-§sensitive properties still suffer from two major §drawbacks: 1) Limit to the use of pH-sensitive §vinylic monomer. Thus, many pH-sensitive polymers §like bio- and synthetic polymers cannot be used. 2) §Phase transition temperature of the polymer is §influenced by protonation degree of §the pH-sensitive polymer. In this book, a novel §method to prepare smart microgels that consist of §well-defined temperature-sensitive cores §with pH-sensitive shells is described in details.§The microgels are synthesized directly from aqueous §graft copolymerization of N-isopropylacrylamide or N-§vinylcaprolactam with a crosslinker, from water-§soluble polymer of poly(ethyleneimine) or chitosan. §The well-defined core-shell nanostructure exhibits §tuneable responses to pH, temperature and §electrolyte changes. Thus, this new type of smart §materials should be extremely useful in drug §delivery, biosensing, separation technology, etc.