Radical Mediated New Dynamic Covalent Bond and Resulting Mechanically Enhanced Toughened Interlocked Interpenetrating Networks

The reaction between disulfide bonds and nitroxide radicals is found to form a dynamically covalent NOS bond. This dynamic covalent bond not only retains exchange characteristics of traditional dynamic covalent bonds but also can engage in multimodal exchange reactions with thiols, disulfides, and nitroxide radicals. A reversible interlocked polymer network is constructed by deinterlocking and reinterlocking two-polymer networks respectively containing disulfides and alkoxyamines bonds, which significantly enhances and toughens mechanical properties as a result of formed dynamic NOS bonds between networks and interpenetrating structures. The high content of hydrogen bonds within the interlocked network endows the material with excellent adhesive properties, making it suitable for automotive applications. Additionally, its multidynamic bonds (NOS, disulfides, and alkoxyamines) enable efficient self-healing of scratches. Our work provides an innovative approach for the design of new dynamic covalent bonds and mechanically enhanced toughened polymers based on radical chemistry.