Fundamental Insights into Free-Radical Polymerization in the Presence of Catechols and Catechol-Functionalized Monomers

Abstract

Polymers containing catechols are attractive for use in a diverse range of applications. However, the direct incorporation of catechols is challenging in polymers produced by radical polymerization due to transfer and termination reactions that readily occur between catechols and radical species. In this work, it is demonstrated that while monosubstituted olefins such as styrene and methyl acrylate readily undergo chain transfer to phenolic hydrogens, methacrylic monomers do not suffer any inhibitory activity and can be polymerized to high molecular weights without any influence of the catechol, even when the catechol is present in large amounts (50 wt %). In addition, it is demonstrated that even for the polymerization of monosubstituted olefins, the inhibitory activity of catechols can be substantially reduced by the selection of polar solvents such as dimethyl formamide. Thus, through appropriate selection of monomers and reaction conditions, it is shown that catechol-containing monomers can be readily incorporated into polymers obtained by free radical polymerization without any protection/deprotection of the catechol.

Designing a Naturally Inspired Conductive Copolymer to Engineer Wearable Bioadhesives for Sensing Applications

“…Recent studies have shown that polar solvents with a strong hydrogen bonding ability to phenol groups could prevent side reactions of catechol in radical polymerizations. This allows for the synthesis of copolymers with dopamine side chains without requiring any protection for diol groups. , In this study, RAFT polymerization was employed to synthesize a novel adhesive and conductive bioinspired copolymer p­(METAC-DMA), as shown in Figure a. This biocompatible and multifunctional copolymer possessed adhesive and conductive properties due to its appropriate functional units (dopamine and choline), which can be combined with any biopolymers containing amine groups in an oxidative environment to form conductive and bioadhesive hydrogels.…”

Solid-phase synthesis of iterative RAFT single unit monomer insertion adducts

“…We observe the key difference in the required reaction time between additions of indene and phenylmaleimide is from an extended induction period which we attribute to oxygen-containing inhibiting species (specifically those which operate via chain transfer) generally being more effective on electron-rich monomers than those that are electron-deficient. 44 We hypothesise that such species would form upon generating hydrogen peroxide from the reaction of singlet oxygen (generated from the catalyst) with ascorbic acid. However, we have not confirmed these species (or even the presence of hydrogen peroxide) spectroscopically.…”

Janus metallic film with gold and silver luster by electroless deposition of silver using poly(dopamine acrylamide) thin film

“…A previous study indicated that catechol OH groups are protected by hydrogen bonding with DMF. 16 We believe this “on-demand protection” enables control of the RAFT polymerization of unprotected DOPAm. Subsequently, the polymer obtained after 360 min was purified by reprecipitation and characterized by 1 H NMR spectroscopy.…”