Thermo‐Responsive Brush Copolymers by “Grafting Through” Strategy Implemented on the Surface of the Macromonomer Micelles and Their High Emulsifying Performance

In the present study, the synthesis of water‐soluble thermo‐responsive brush copolymers via “graft through” strategy that is conducted on the surfaces of macromonomer micelles and their application as emulsifiers for thermo‐responsive emulsions are reported. Water‐soluble poly(N ,N‐dimethylacrylmide)‐block‐poly(N‐isopropylacrylmide) (PDMA‐b‐PNIPAM) diblock copolymers carrying a hydrophobic polymerizable vinyl group at the end of the PDMA block are synthesized by reversible addition‐fragmentation chain transfer polymerization and click functionalization. Increasing the temperature to above the low critical solution temperature of the PNIPAM block, the macromonomers self‐assemble to core–shell structure micelles with the polymerizable vinyl terminals on the surface of the micelles. Instead of being directly and freely exposed in the bulk water as the hydrophilic group, the hydrophobic vinyl terminals are protected by the partially looped PDMA segments. PMA‐g‐(PDMA‐b‐PNIPAM) brush copolymers with a high molecular weight and a narrow distribution are obtained by radical polymerization of the macromonomers using the potassium peroxydisulfate as initiator. The radical polymerization only proceeds within the single micelle, and intermicellar propagation and/or termination reactions are totally excluded. These brush copolymers feature the thermo‐responsive conformation transition property and high emulsifying performances for the formation of thermo‐responsive emulsion.