LAUSR

We describe a facile method for the synthesis of microgels with covalent and noncovalent ionic cross-links. Microgels were synthesized by copolymerization of various N-vinyllactams with zwitterionic monomer (methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide in the presence of a cross-linking agent (bis(acrylamide)) in water-in-oil emulsion. Monodisperse colloidally stable microgels with a high amount (>30 mol %) of zwitterionic groups were synthesized. High contents of zwitterionic groups in microgels led to the formation of reversible ionic cross-links along with permanent covalent cross-links generated by bis(acrylamide). The obtained microgels exhibit interesting temperature-triggered swelling/deswelling behavior in aqueous solution. With an increase of the temperature above 10 °C, the microgels swell due to the destruction of the zwitterionic cross-links. Above the lower critical solution temperature of poly(N-vinyllactam) chains at T > 32 °C, the microgels shrink due to the destruction...