Polymer nanoparticles via intramolecular crosslinking of sulfonyl azide functionalized polymers

A new approach to prepare polymeric nanoparticles via intramolecular collapse of single chain of sulfonyl azide functionalized polymers is proposed. Upon heating, the sulfonyl azide functionalized linear copolymers lose nitrogen and form nitrene. This nitrene reacts with CH bond of the backbone in dilute solution and leads to the efficient intramolecular crosslinking and formation of nanoparticles where the diameter of nanoparticles can be controlled by both the molecular weight and the content of sulfonyl azide groups. A significant reduction in the hydrodynamic volume is observed on going from the starting random coil of linear chains to the corresponding nanoparticles. The morphology and the dimension of nanoparticles are characterized by using transmission electron microscope (TEM), atomic force microscopy (AFM), as well as dynamic laser scattering (DLS).