Efficient and Generic Preparation of Diverse Polyelectrolyte Nanogels by Electrostatic Assembly Directed Polymerization

Nanogels hold promise as soft and functional carriers and nanoreactors, butwhether theywill ever reach the stage of large-scale application depends crucially on efficient productionmethods, and on what interesting properties and functionalities they can have. In particular, nanogels consisting of highly charged polyelectrolyte have not yet been very much explored. Here, the authors present a novel and generic strategy for controlled and efficient synthesis of a large diversity of polyelectrolyte nanogels. The method is based on polymerizing an ionic monomer in the presence of an oppositely charged polyion-neutral diblock copolymer as template, while adding a cross-linker. The growing polymer chains assemble with the template, forming polyion complex micelles, which dissociate upon increasing salt concentration. Subsequent separation yields nanogels with well-controlled size and properties, and free template polymers that can be used again. Our design can be applied generally to a wide range of both cationic and anionicmonomers, as well as various cross-linkers. Scaled-up production presents no problems as increasingmonomer concentration (hundreds of mM) and reaction volume (up to 1 L) hardly compromise product quality. Moreover, the obtained nanogels with their well-controlled size, morphology, chemistry, and cross-linking degree performwell as soft nanocarriers and catalytic nanoreactors.