Star polymer nanoshells and methods of preparation thereof

A tagged silica nanoshell, comprising:

• a star polymer occlusion complex comprising i) an amphiphilic unimolecular star polymer having a crosslinked polymer core covalently linked to 6 or more independent polymer arms and ii) a cargo material occluded in the star polymer, wherein the crosslinked polymer core is a product of a vinyl polymerization and/or a ring opening polymerization;
• a shell comprising silica exterior to and in contact with a peripheral surface of the star polymer occlusion complex;
• and
• an organic surface group comprising a poly(alkylene oxide) chain segment covalently linked to the shell.

A method, comprising:

• treating a star polymer occlusion complex with a first tetravalent silicon material, thereby forming a precursor silica nanoshell, wherein i) the star polymer occlusion complex comprises an amphiphilic unimolecular star polymer and a cargo material occluded therein, the star polymer having a crosslinked polymer core covalently linked to 6 or more independent polymer arms and ii) the crosslinked polymer core is a product of a vinyl polymerization and/or a ring opening polymerization;
• treating the precursor nanoshell with a second tetravalent silicon material comprising a nucleophilic group, thereby forming a silica nanoshell comprising a shell, wherein the shell comprises i) silica exterior to and in contact with a peripheral surface of the star polymer occlusion complex and ii) nucleophilic surface groups selected from the group consisting of amines, thiols, alcohols, and combinations thereof;
• and
• covalently linking to a nucleophilic surface group of the shell an organic surface group comprising a poly(alkylene oxide) chain segment, thereby forming a tagged silica nanoshell.