Grubbs’ and Schrock’s Catalysts, Ring Opening Metathesis Polymerization and Molecular Brushes—Synthesis, Characterization, Properties and Applications

Abstract

In this review, molecular brushes and other macromolecular architectures bearing a bottlebrush segment where the main chain is synthesized by ring opening metathesis polymerization (ROMP) mediated by Mo or Ru metal complexes are considered. A brief review of metathesis and ROMP is presented in order to understand the problems and the solutions provided through the years. The synthetic strategies towards bottlebrush copolymers are demonstrated and each one discussed separately. The initiators/catalysts for the synthesis of the backbone with ROMP are discussed. Syntheses of molecular brushes are presented. The most interesting properties of the bottlebrushes are detailed. Finally, the applications studied by different groups are presented.

Synthesis of well‐defined norbornenyl‐terminated poly(alkyl methacrylate)s by group transfer polymerization and their grafting‐through ring‐opening metathesis polymerization

“…ROMP of highly lipophilic NB-PEHMA was evaluated in polar THF (entries 10-12) and nonpolar 1,2-dichloroethane (1,2-DCE) (entries 13-15); the solvent effect on bottlebrush polymer growth was profound. At a low [MM]/[G3] ratio of 50, the reaction in THF exhibited superior control compared to the reaction in 1,2-DCE, with a narrow unimodal molecular-weight distribution (entries 10 and 13, red lines in Figure 3a Finally, the polar macromonomer NB-PEEMA was evaluated (entries [16][17][18][19][20]. It exhibited a good conversion only in the case of [MM]/[G3] = 50 (94%, Entry 16), and quickly lost its polymerization efficiency as the ratio of macromonomer to G3 increased.…”

“…Furthermore, combined with the controlled/living synthesis of macromonomers, bottlebrush polymers possessing finely tuned structures and properties have become accessible. [15][16][17][18][19][20] The methacrylate polymer is among the most abundant polymers utilized in numerous applications, 21,22 and as such, it is surprising that its use in bottlebrush polymers extends to a few limited cases, especially involving the grafting-through process. Norbornenyl-terminated polymethacrylates are synthesized by anionic polymerization [23][24][25] or reversible-addition-fragmentation-transfer (RAFT) radical polymerization with a norbornene group containing an initiator or a terminator.…”

Coordination‐Insertion Copolymerization of Norbornene and p‐Substituted Styrenes Using Anilinonaphthoquinone‐Ligated Nickel Complexes

“…Three polymerization methods are commonly used for preparing poly(norbornene)s (PNBs): ring‐opening metathesis polymerization (ROMP),1 cationic or radical polymerization,2,3 and coordination‐insertion polymerization 4. Coordination‐insertion polymerization of norbornene (N) results in PNB consisting of linked strained rings, which exhibits remarkable improvements in physical properties such as good heat and chemical resistance, high glass transition temperature ( T g ), high optical transparency, and low dielectric constant 4,5.…”

Strain‐promoted azide‐alkyne cycloaddition polymerization as a route toward tailored functional polymers

“…Traditional radical, condensation, and ionic polymerizations significantly limit the scope of polymerizable monomers as a result of the harsh reaction conditions and reagents required to produce high molecular weight polymers 1,2 . Although numerous new polymerization reactions have been developed, including controlled radical polymerization, such as nitroxide‐mediated (NMP), 3,4 atom transfer (ATRP), 5,6 reversible addition‐fragmentation chain‐transfer (RAFT), 7,8 transition metal‐mediated cross‐coupling, 9 ring‐opening metathesis polymerization (ROMP), 10–12 and others, 13–18 many of these still require the use of catalysts and high temperatures to carry out the polymerization. Therefore, exploration of additional polymerization reactions is warranted in order to enable introduction of sensitive functionality.…”