Solvent-controlled formation of star-like nanogels via dynamic covalent exchange of PSt- b -PMMA diblock copolymers with alkoxyamine units in the side Chain

Solvent-controlled formation of star-like nanogels via a dynamic covalent exchange reaction of Polystyrene-b-poly(methyl methacrylate) (PSt-b-PMMA) diblock copolymers with alkoxyamine units in the PMMA block was shown. Diblock copolymers, consisting of PSt blocks and PMMA blocks with cross-linkable alkoxyamine units, were synthesized by ATRP techniques. The results show that a dynamic covalent exchange among alkoxyamine units in the polymer side chains makes it possible to form cross-linking structures from linear polymers. The molecular weights and sizes of the star-like nanogels are found to depend on their reaction time, the mixing ratio of two types of diblock copolymers, and reaction concentrations. The results also show that the sizes of star-like nanogels are different, and the diameter and height values in decalin are more than triple than those in anisole.