Facile Access to <i>gem</i>-Trifluoromethyl/Boron-Functionalized Polymers via Free-Radical Copolymerization and Cotelomerization

Functional fluoropolymers are important for various applications due to the integrated characteristics of functional groups and fluorocarbon segments. Herein, we developed (1) thermally initiated and visible-light-initiated copolymerization of (trifluoromethyl)­vinyl boronic esters (CF3VBs) and unconjugated alkenes (18 examples, including vinyl ethers, esters, and amides), enabling the efficient synthesis of a broad scope of fluoropolymers in 71–92% yield and variable fractions of gem-CF3/B substituents (FCF3VB = 0.26–0.84) at different molar masses (Mn = 5.2–33.4 kDa) and (2) visible-light-initiated cotelomerization of CF3VB and unconjugated alkenes with p-tolyl disulfide as a telogen (Mn = 3.6–13.0 kDa). Reactivity ratios for copolymerization were determined by the Meyer–Lowry method at 65 °C (for BVE: rCF3VB = 1.254, rBVE = 0.006; for VAc: rCF3VB = 0.235, rVAc = 0.042; for NVP: rCF3VB = 1.067, rNVP = 0.063). The achieved high fractions of CF3VBs in copolymers are also confirmed by density functional theory (DFT) calculation results. Through post-polymerization modifications, gem-CF3/B units could transform into various copolymers and terpolymers with geminal functionalities (e.g., gem-CF3/OH, gem-CF3/vinyl, gem-CF3/furan). The increase of geminal functionalities enables clearly amplified chemical responsiveness toward pH variation, as demonstrated by fluoropolymers with gem-CF3/OH

Organocatalyzed Controlled Copolymerization of Perfluorinated Vinyl Ethers and Unconjugated Monomers Driven by Light

Perfluorinated vinyl ethers (PFVEs) are an important category of monomers for producing fluoropolymers that have found broad applications. In this work, by developing a dibenzo­[a,c]­phenothiazine-based organic photoredox catalyst, we realize photo-controlled radical copolymerization of various PFVEs and unconjugated comonomers (e.g., vinyl esters, vinyl amides, and vinyl ethers) with a high reaction efficiency when exposed to visible-light irradiation, affording a large series of main- and side-chain fluorinated copolymers of low dispersities (D̵ = 1.06–1.24) and good chain-end fidelity at excellent conversions of unconjugated comonomers. Furthermore, this method not only facilitates the “ON/OFF” temporal switch of the chain growth with tunable kinetics for the “ON” states upon altering the wavelengths of light sources but also allows photo-controlled chain extensions with copolymers and homopolymers as additional blocks, presenting a facile and versatile platform to customize complex fluoropolymers for material engineering