Amphiphilic gradient copolymer of [poly(ethylene glycol) methyl ether] methacrylate and styrene via atom transfer radical polymerization

Well-defined amphiphilic gradient copolymers of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and styrene were successfully synthesized using atom transfer radical polymerization. The relative reactivity ratio of PEGMA to styrene was determined using the Jaacks method. The initial feed ratio of the two monomers had a significant effect on the copolymer's gradient composition. The resultant copolymers were characterized by nuclear magnetic resonance and Fourier transform-infrared spectroscopy to confirm their structures and monomer compositions. The lower critical solution temperature behavior of the copolymers was investigated using ultravioletvisual spectroscopy. The micellization behavior of the PEGMA and styrene copolymers in aqueous solution was observed by transmission electron microscopy and dynamic laser scattering.