Practical Synthesis of Dendritic Hyperbranched Polyacrylates and Their Topological Block Polymers by Organotellurium‐Mediated Emulsion Polymerization in Water**

Abstract

The practical synthesis of structurally controlled hyperbranched polymers (HBPs) by organotellurium‐mediated radical polymerization (TERP) in water under emulsion conditions is reported. Copolymerization of vinyltelluride named evolmer, which induces controlled branch structure, and acrylates with TERP chain transfer agent (CTA) in water afforded HBPs having dendron structure. The molecular weight, dispersity, branch number, and branch length of the HBPs were controlled by changing the amount of CTA, evolmer, and acrylate monomers. HB‐poly(butyl acrylate)s (HBPBAs) with up to the 8th generation having an average of 255 branches were successfully synthesized. As the monomer conversion reached nearly quantitative and the obtained polymer particles were well dispersed in water, the method is highly suitable for synthesizing topological block polymers, block polymers consisting of different topologies. Thus, linear‐block‐HB, HB‐block‐linear, and HB‐block‐HB‐PBAs with the controlled structure were successfully synthesized by adding the second monomer(s) to the macro‐CTA. The intrinsic viscosity of the resulting homo‐ and topological block PBAs was systematically controlled by the degree of the branch, the branch length, and the topology. Therefore, the method opens the possibility of obtaining various HBPs with diverse branch structures and tuning the polymer properties by the polymer topology.

Impact of Interfacial Halogen Bonding with a Surfactant on Miniemulsion Reversible Chain Transfer-Catalyzed Polymerization

“…In RDRPs, the key control mechanism is the reversible deactivation of radical species; that is, active radicals generated from initiators can be quickly deactivated to dormant species and the dormant species can be activated to radical species again. Various RDRP mechanisms have been developed, including nitroxide-mediated polymerization (NMP), − atom transfer radical polymerization (ATRP), − reversible addition–fragmentation chain transfer (RAFT) polymerization, − organotellurium-mediated living radical polymerization (TERP), , and single-electron transfer living radical polymerization (SET-LRP). , …”

Hydrophilic Poly(meth)acrylates by Controlled Radical Branching Polymerization: Hyperbranching and Fragmentation

“…56 TERP under emulsion conditions in water using Brij 98 surfactant for the synthesis of highly branched poly(n-butyl acrylate) was reported. 57 ATRP of acrylates in water is still considered a challenge due to potential hydrolysis of the C(sp 3 )−X (secondary halides are more prone to hydrolysis than tertiary), leading to loss of chain-end functionality since the C(sp 3 )−OH cannot participate in further chain growth. 58−60 Second, the high values of equilibrium constant of ATRP in water lead to a high concentration of radicals, which may result in more dead chains.…”

“…Our group extended the application of ATRP method in water using a water-soluble ionic inibramer sodium 2-bromoacrylate (SBA) with improved copolymerization kinetic parameters to synthesize hydrophilic hyperbranched polymethacrylates . TERP under emulsion conditions in water using Brij 98 surfactant for the synthesis of highly branched poly­( n -butyl acrylate) was reported …”

“… 56 TERP under emulsion conditions in water using Brij 98 surfactant for the synthesis of highly branched poly( n -butyl acrylate) was reported. 57 …”

One-Pot Synthesis, Circularly Polarized Luminescence, and Controlled Self-Assembly of Janus-Type Miktoarm Star Copolymers

“…The preparation of polymers with well-defined structures and compositions has attracted increasing attention over the past several decades. − Polymer chemists have developed a tremendous variety of polymers with different chemical structures, e.g., linear polymers, − star polymers, − polymer brushes, − dendritic polymers, − and Janus-type polymers. − Among them, Janus-type polymers have emerged as a special class of polymers having an asymmetric structure and are receiving particular attention. The reported Janus-type polymers are mainly Janus dendritic polymers, , Janus miktoarm star polymers, , and Janus polymer brushes. , For example, Percec and co-workers have done an important milestone work on Janus dendrimers .…”