Novel Amphiphilic Centipede-Like Copolymer Bearing Polyacrylate Backbone and Poly(ethylene glycol) and Polystyrene Side Chains

A series of well-defined asymmetric centipede-like copolymers, containing polyacrylate backbone, hydrophilic poly(ethylene glycol), and hydrophobic polystyrene side chains, was synthesized by successive atom transfer radical polymerization. The grafting-through strategy was first employed for the preparation of polypoly(ethylene glycol) methyl ether acrylate comb copolymer. The grafting-from route was used following for the synthesis of the final amphiphilic centipede-like copolymer, polypoly(ethylene glycol) methyl ether acrylate- g -polystyrene. At each grafting point, two different chains are connected and the spacing between the grafting points is constant. Polystyrene side chains were connected to the polyacrylate backbone through stable C−C bonds instead of ester connections. The molecular weights of both the backbone and the side chains were controllable. The molecular weight distributions were in the range of 1.24−1.38. The critical micelle concentrations of these amphiphilic centipede-like graft copolymers in water were determined by fluorescence probe technique. The morphologies of the micelles formed from these centipede-like graft copolymers were preliminarily explored by TEM and were found to be spheres.