Silicone Self-Healing Materials

Silicone self-healing materials are widely used in wearable equipment, smart coatings and other fields. In this review, we detail the self-healing properties, mechanism and latest research progress for both extrinsic and intrinsic silicone self-healing materials. In the section of extrinsic silicone self-healing materials, a variety of silicone-specific reactions, including light-induced radical reaction, condensation curing and hydrosilylation, that have been exploited to achieve self-healing properties are discussed. Similarly, mechanisms to achieve intrinsic self-healing through reversible chemical reactions, metal-ligand coordination, supramolecular interaction and other methods are described in the following section, as well as their properties. To be more specific, reversible chemical reactions could be divided into Diels-Alder reaction, acylhydrazone bonds, ester bonds and Schiff-base bonds, while supramolecular interactions consist of hydrogen bonding and pi-pi stacking. Besides, some other self-healing systems such as minimizing surface free energy, thiol-silver nanoparticles interaction and reconstruction reaction are introduced. Based on the review, a brief appraisal of the challenges and orientation for future developments in this field is presented.