Fluorous Comonomer Modulates the Reactivity of Cyclic Ketene Acetal and Degradation of Vinyl Polymers

Abstract

Fluorine-containing polymers have potential for use in medicine and other applications, but the synthesis of degradable fluorous polymers is underexplored. In this report, we present a facile route to degradable fluorinated polymers and characterize the effect of fluorous comonomer identity on the polymerization as well as the degradation kinetics of the resulting polymer. Copolymers of poly­(ethylene glycol methyl ether methacrylate) (PEGMA), fluorous methacrylate (1H,1H,2H,2H-perfluorooctyl or 1H,1H,2H,2H,3H,3H-perfluoropentyl methacrylate), and cyclic ketene acetal 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) were synthesized via ruthenium-catalyzed living radical polymerization. It was observed that increasing the fluorous monomer content led to enhanced BMDO incorporation in the resulting polymer. Density functional theory calculations suggest that this is due to the decreased energy gap between the singly occupied molecular orbital (SOMO) of the methacrylate radical and the highest occupied molecular orbital (HOMO) of BMDO. Moreover, polymers with higher fluorous monomer content were more hydrolytically stable, with a degradation rate constant 100-fold smaller for the polymer with highest fluorous content compared to the nonfluorous polymer. This work provides easy access to degradable fluorous polymers using vinyl monomers. In addition, the insights gained into modulation of reactivity of cyclic ketene acetals and polymer degradation will be useful in applying fluorous polymers for a variety of biomedical applications.

Fully Degradable Thioester-Functional Homo- and Alternating Copolymers Prepared through Thiocarbonyl Addition–Ring-Opening RAFT Radical Polymerization

“…32 Notably, the estimated reactivity ratios for DOT-PhMI and DOT-PFPMI were similar to those observed for alternating CKA-based copolymers, e.g. Finally, 19 F NMR spectroscopy was used to demonstrate the versatility of backbone thioesters. A spectrum of the intact copolymer p(DOT-alt-PFPMI) is shown in Figure 6A.…”

“…Unfortunately, the realisation is far from trivial as most radical copolymerizations involve disparate monomer reactivities and result in copolymers with a compositional gradient. 19,20 Recently, Shi and Agarwal 21 and Hill and co-workers 22,23 investigated the copolymerization of CKAs with N-functional maleimides. These electron-poor monomers are have been known to prefer alternating copolymerization 24 with electron-rich comonomers, such as styrene, 25,26 although this behaviour is not apparent with most other vinyl comonomers.…”

100th Anniversary of Macromolecular Science Viewpoint: Degradable Polymers from Radical Ring-Opening Polymerization: Latest Advances, New Directions, and Ongoing Challenges

“…In this context, the synthesis of degradable fluorinated polymers by ruthenium-catalyzed living radical terpolymerization of BMDO with fluorinated methacrylates (1 H ,1 H ,2 H ,2 H -perfluorooctyl or 1 H ,1 H ,2 H ,2 H ,3 H ,3 H -perfluoropentyl methacrylate) and oligo­(ethylene glycol) methacrylate (OEGMA) has been recently reported for potential use in medicine and other applications (Figure ). It was demonstrated that increasing the fluorinated monomer content led to (i) enhanced BMDO incorporation in the resulting terpolymer and (ii) a 100-fold higher hydrolytic stability compared to the nonfluorinated counterpart.…”

DFT-calculation-assisted prediction of the copolymerization between cyclic ketene acetals and traditional vinyl monomers

“…It should be noted that Maynard and Sawamoto recently showed that degradable methacrylatebased copolymers with pendant fluorinated group could also be prepared by the copolymerization of BMDO and fluorinated methacrylate. 42 Our system is thus another straightforward methodology to prepare degradable fluorinated copolymers with the fluorinated group directly linked to the backbone and not only present as a pendant group.…”