Abstract: Poly(ethylene glycol) (PEG) macromolecular brushes were synthesized directly via re-versible addition-fragmentation chain transfer polymerization cyclopolymerization of diacry-late monomers bearing PEG functional groups through the formation of 11-member rings. The diacrylate monomers bearing PEG functional groups are the 1,2,3-triazole-tethered di-acrylate macromolecular monomers with different PEG lengths synthesized via the so-called “click” chemistry. The bulky hindrance of PEG chains affected the polymerization behavior of the diacrylate macromolecular monomers, and the diacrylate monomers showed strong tendency to cyclopolymerization rather than crosslinking. NMR analysis and gel perme-ation chromatography profiles proved the high e ciency of cyclopolymerization without sidereactions. The aqueous solutions of the obtained PEG macromolecular brushes were fluores-cent under UV excitation. The uorescence depended dramatically on the concentration of brush-like polymers due to the aggregation of cyclopolymer in water, and could be quenched by the addition of DNA.