Translating the precise monomer sequence control achieved in nature over macromolecular structure (for example, DNA) to whole synthetic systems has been limited due to the lack of efficient synthetic methodologies. So far, chemists have only been able to synthesize monomer sequence-controlled macromolecules by means of complex, time-consuming and iterative chemical strategies such as solid-state Merrifield-type approaches or molecularly dissolved solution-phase systems. Here, we report a rapid and quantitative synthesis of sequence-controlled multiblock polymers in discrete stable nanoscale compartments via an emulsion polymerization approach in which a vinyl-terminated macromolecule is used as an efficient chain-transfer agent. This approach is environmentally friendly, fully translatable to industry and thus represents a significant advance in the development of complex macromolecule synthesis, where a high level of molecular precision or monomer sequence control confers potential for molecular targeting, recognition and biocatalysis, as well as molecular information storage.
Usually atom transfer radical polymerization (ATRP) requires various parameters, such as the type of initiator, transition metal, ligand, solvent, temperature, deactivator, added salts and reducing agents, need to be optimised in order to achieve a high degree of control over molecular weight and dispersity. These components play a major role when switching monomers e.g. from acrylic to methacrylic and/or styrenic monomers during the synthesis of homo-and block copolymers as the stability and reactivity of the carbon centered propagating radical dramatically changes. This is a challenge for both "experts" and non-experts as choosing the appropriate conditions for successful polymerization can be time consuming and an arduous task. In this work we describe some universal conditions for the efficacious polymerization of acrylates, methacrylates and styrene (using an identical initiator, ligand, copper salt and solvent) based on commercially available reagents (PMDETA, IPA, Cu(0) wire). The versatility of these conditions is demonstrated by the near quantitative polymerization of these monomer families to yield well-defined materials over a range of molecular weights with low dispersities (~1.1-1.2). The control and high end group fidelity is further exemplified by in situ block copolymerization upon sequential monomer addition for the case of methacrylates and styrene furnishing higher molecular weight copolymers with minimal termination. The facile nature of these conditions, combined with readily available reagents will greatly expand the access and availability of tailored polymeric materials to all researchers.
As a method for overcoming the challenge of rigorous deoxygenation in copper‐mediated controlled radical polymerization processes [e.g., atom‐transfer radical polymerization (ATRP)], reported here is a simple Cu0‐RDRP (RDRP=reversible deactivation radical polymerization) system in the absence of external additives (e.g., reducing agents, enzymes etc.). By simply adjusting the headspace of the reaction vessel, a wide range of monomers, namely acrylates, methacrylates, acrylamides, and styrene, can be polymerized in a controlled manner to yield polymers with low dispersities, near‐quantitative conversions, and high end‐group fidelity. Significantly, this approach is scalable (ca. 125 g), tolerant to elevated temperatures, compatible with both organic and aqueous media, and does not rely on external stimuli which may limit the monomer pool. The robustness and versatility of this methodology is further demonstrated by the applicability to other copper‐mediated techniques, including conventional ATRP and light‐mediated approaches.
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