Biocatalytic Hybrid Nanoparticles for Degassing and Stabilization of Single Electron Transfer-Living Radical Polymerization in Pick-ering emulsions

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Sweden is a country covered by forests, providing more than ten percent of the sawn timber and pulp and paper traded on the global market. Besides traditional products of the forest industry, lignin is emerging as an important renewable raw material for new applications. Lignin gives trees their structural rigidity and protection against ultraviolet irradiation and decomposition by insects and microbes. Although classically viewed as a low-value byproduct from chemical pulping processes, our research is focused on harnessing the attractive functional properties of lignin for the production of high-performance materials. Here we show that lignin nanoparticles (LNPs) coated with chitosan and glucose oxidase (GOx) enable efficient stabilization of Pickering emulsion and in situ enzymatic degas-sing of single electron transfer-living radical polymerization (SET-LRP) without extraneous hydrogen peroxide scavengers. The obtained polymers exhibit high chain end fidelity that allows for production of a series of well-defined block copolymers as a viable route to more complex architectures. Our breakthrough is of broad importance because oxygen sensitivity is a roadblock to industrial adaptation of controlled synthesis of well-defined polymers e.g. for functional coatings, drug release systems. Additionally, we also showed that the polymerization process opens a straightforward route to fabricate lignin-based polymer composites with a green carbon footprint by simple melting process. These last findings are of key importance because this way one can overcome the formidable challenge of homogeneously mixing lignin within incompatible polymeric matrixes.