Research progress of self-healing coatings based on dynamic covalent crosslinking

It is an important barrier for coating materials to resist external stress damage, with the development of science and technology, intelligent coating can endow the original coating with advanced functions such as fluorescence, antibacterial, detection and sensing, etc. However, it will inevitably suffer from mechanical damage (such as scratches, scratches, etc.) and macroscopic or microscopic damage caused by stress mismatch with internal components, which will lead to cracks or even cracks, and structural damage will lead to functional weakening or even disappearance. Therefore, higher requirements were put forward for the structural stability and functional continuity of the coating. The self-healing coatings, based on dynamic covalent cross-linking network, can establish a thermodynamic equilibrium between the raw materials molecules and product molecules, and obtain the self-healing capacity via the recombination of dynamic network. The activation energy value of dynamic network not only directly reflects ease of healing reaction (i.e., reaction rate), but also affects the mechanical performance of the resultant materials. In this paper, we discuss and clarify the relationship between the construction of self-healing network and activation energy of reaction according to the chemical thermodynamics, subsequently, we comment the applications of the self-healing coatings with dynamic covalent cross-linking network in the fields of traditional coatings, intelligent sensor, photochromic, biological medicine. Finally, we prospect the developed bottleneck and perspective of the dynamic covalent self-healing coatings. © 2023 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.