The synthesis by reversible addition-fragmentation chain transfer (RAFT) polymerization of three phosphonated terpolymers with tailored architecture has been studied. A phosphonated methacrylate (MAUPHOS) was copolymerized with vinylidene chloride (VC2) and methyl acrylate (MA) to prepare a gradient terpolymer poly(VC2-co-MA-co-MAUPHOS). Besides, hydroxyethyl acrylate (HEA) was used as a functional monomer in RAFT polymerization to prepare a statistical poly(VC2-co-MA-co-HEA) terpolymer and a diblock poly(VC2-co-MA)-b-poly(HEA) terpolymer. The HEA-containing polymers were then modified with a phosphonated epoxide to introduce the phosphonated group. The control of the polymerization was proven by kinetic studies (evolution of molecular weight vs. conversion) and by a successful block copolymerization. The architecture of the terpolymers was determined by the reactivity ratios of the monomers: terpolymerization of VC2, MA, and HEA leading to an ideal statistical terpolymer (no composition drift) whereas terpolymerization of VC2, MA, and the phosphonated methacrylate led to a gradient terpolymer. These terpolymers were characterized by size exclusion chromatography, P-31 NMR and differential scanning calorimetry. (c) 2005 Wiley Periodicals, Inc.