Zwitterionic double network hydrogels, methods for making zwitterionic double network hydrogels, methods for using zwitterionic double network hydrogels, and articles made from and coated with zwitterionic double network hydrogels.

The present invention relates to thermally expandable thermoplastic microspheres comprising a polymer shell made from ethylenically unsaturated monomers encapsulating a propellant, said ethylenically unsaturated monomers comprising from 21 to 80 wt % of methacrylamide and from 20 to 70 wt % methacrylonitrile, the total amount of methacrylamide and methacrylonitrile being from 70 to 100 wt % of the ethylenically unsaturated monomers. Furthermore, the invention relates to production and use of such microspheres.

Zwitterionic double network hydrogels, methods for making zwitterionic double network hydrogels, methods for using zwitterionic double network hydrogels, and articles made from and coated with zwitterionic double network hydrogels.