Chain‐growth polymerization of azide–alkyne difunctional monomer: Synthesis of star polymer with linear polytriazole arms from a core

Abstract

This article reports a chain‐growth coupling polymerization of AB difunctional monomer via copper‐catalyzed azide–alkyne cycloaddition (CuAAC) reaction for synthesis of star polymers. Unlike our previously reported CuAAC polymerization of AB n (n ≥ 2) monomers that spontaneously demonstrated a chain‐growth mechanism in synthesis of hyperbranched polymer, the homopolymerization of AB monomer showed a common but less desired step‐growth mechanism as the triazole groups aligned in a linear chain could not effectively confine the Cu catalyst in the polymer species. In contrast, the use of polytriazole‐based core molecules that contained multiple azido groups successfully switched the polymerization of AB monomers into chain‐growth mechanism and produced 3‐arm star polymers and multi‐arm hyperstar polymers with linear increase of polymer molecular weight with conversion and narrow molecular weight distribution, for example, Mw/Mn ~ 1.05. When acid‐degradable hyperbranched polymeric core was used, the obtained hyperstar polymers could be easily degraded under acidic environment, producing linear degraded arms with defined polydispersity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 84–90

Bioorthogonal Chain-Growth Polymerization: Site-Specific Labeling of Artificial Polymers in Living Cells

“…In this case, the triazole produced during the CuAAC reaction can bind with Cu(I) and act as a catalyst, enabling the reaction to occur in the periphery of the branched polymers 34,35 . Nevertheless, in the case of linear polymerization, there are certain undesired reactions between monomer and monomer 30 .…”

Chain-Growth Sulfur(VI) Fluoride Exchange Polycondensation: Molecular Weight Control and Synthesis of Degradable Polysulfates

“…Most of the examples afforded diverse stepgrowth polymers, while there are few reports of chain-growth type CuAAC polymerization by holding Cu catalysts at the end of the growing chain. 33,34 With another recent click-caliber reaction, SuFEx [sulfur-(VI) fluoride exchange], it is now possible to create stable sulfate and sulfonate links with great ease and reliability. 35,36 Via this approach, we have synthesized polysulfates and polysulfonates, 37−39 in which AA-and BB-type monomers are used as building blocks (Figure 1a), and the polymerization takes place between the fluorosulfate and the silyl ether-bearing monomers in the presence of catalysts such as 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) and 2-tert-butylimino-2-diethylamino-1,3-dimethyl perhydro-1,3,2-diazaphosphorine (BEMP).…”

“…Moreover, complex structures − and higher architectures such as graft and dendronized polymers were also successfully synthesized by using its advanced version (Cu-catalyzed multicomponent polymerization). Most of the examples afforded diverse step-growth polymers, while there are few reports of chain-growth type CuAAC polymerization by holding Cu catalysts at the end of the growing chain. , …”

Chain-Growth SuFEx Polycondensation: Molecular Weight Control and Synthesis of Degradable Polysulfates

“…Most of the examples afforded diverse step-growth polymers, while there are a few reports of chain-growth type CuAAC polymerization by holding Cu catalyst at the end of growing chain. 33,34 With another recent click-caliber reaction, SuFEx [Sulfur (Ⅵ) Fluoride Exchange], it is now possible to create stable sulfate and sulfonate links with great ease and reliability. 35,36 Via this approach, we have synthesized polysulfates and polysulfonates, 37,38 39 in which AA and BB type monomers are used as building blocks (Fig.…”