Vinyl-conjugated monomer (methyl acrylate, MA) and allyl 2-bromopropanoate (ABP)-possessing unconjugated C=C and active C-Br bonds were polymerized via the Cu(0)-mediated simultaneous chain-and step-growth radical polymerization at ambient temperature using Cu(0) as catalyst, N,N,N',N '',N ''-pentamethyldiethylenetriamine as ligand and dimethyl sulfoxide as solvent. The conversion was reached higher than 98% within 20 h. The obtained polymers showed block structure consisting of polyester and vinyl polymer moieties. The Cu(0)-catalyzed simultaneous chain-and step-growth radical polymerization mechanism was demonstrated by NMR, matrix-assisted laser desorption ionization time-of-flight, and GPC analyses. Furthermore, the obtained copolymers of MA and ABP were further modified with poly(N-isopropylamide) through radical thiol-ene "click" chemistry from the terminal double bond. The thermoresponsive behavior of this block copolymer was investigated. (C) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3907-3916