Reversible Deactivation Radical Polymerization

Abstract Reversible deactivation radical polymerization (RDRP), formerly known as living radical polymerization (LRP), is the general name for a family of polymerization techniques. The techniques have in common that the propagating species is a free radical and that an equilibrium exists between active (free radical) species and dormant species. Because of this equilibrium (nearly), all chains grow throughout the polymerization reaction. This leads to polymers with predetermined degree of polymerization and (usually) narrow molar mass distribution. A historical overview of the development of RDRP is provided, and the three most important techniques are discussed in more detail. These three techniques are (1) nitroxide‐mediated polymerization, (2) transition metal‐mediated radical polymerization techniques, such as atom transfer radical polymerization, (3) reversible addition–fragmentation chain‐transfer–mediated polymerization, with most emphasis on the latter two. The general kinetics and some boundary conditions for obtaining low molar mass dispersities ( Đ ) polymers are discussed. Furthermore, the scope and limitations of the three major polymerization techniques are outlined. Apart from the predetermined molar mass and the Đ , RDRP is of particular interest in the synthesis of advanced architectures. These architectures include block copolymers, star‐branched polymers, telechelic polymers, gradient or tapered copolymers, etc. Among the major advantages of RDRP is the fact that most of the benefits of free‐radical polymerization (FRP) are retained. Thus, the possibility to (co)polymerize functional monomers (hydroxyl, epoxy, amide, anhydride, etc) and the possibility to polymerize under nondemanding conditions are typical for FRP as well as for RDRP.