Designing Miktoarm Polymers Using a Combination of Click Reactions in Sequence with Ring-Opening Polymerization

The design and synthesis of a well-defined molecular building block with three orthogonal functionalities which facilitate the construction of ABC-type miktoarm star polymers via a combination of sequential Cu-I-catalyzed cycloaddition of an azide to an alkyne (click) followed by ring-opening polymerization are reported Using this simple and highly versatile methodology, a variety of miktoarm star polymers were prepared which consisted of hydrophilic poly(ethylene glycol) and hydiophobic polystyrene and poly(c-caprolactone) arms Their self-assembly in an aqueous medium was examined using dynamic light scattering and transmission electron microscopy These A BC miktoarm polymers were found to self-assemble into spherical micelles whose core size and hydrodynamic diameter were found to be inversely proportional to the size of the PEG arm. The potential of encapsulating Manna small molecules into these micelles was explored using Disperse Red I dye An enhancement in the loading capacity of the micelles was observed with an increase in the length of the hydiophobic arm