Photothermal process and its stimulate healing performance for catalyst-free OCB/epoxy vitrimer composite

Polymeric coatings, widely used in large-scaled outdoor applications including solar energy collection, metal protection and so on, are limited by short service life caused by degradation and structural damage due to constant exposure in air and external force. Here, oxidized carbon black (OCB)/epoxy vitrimer (EV) composite without catalysts, dispersants and pre-heating was prepared by facile solvent mixing method. The addition of OCB improved the stress relaxation rate of the composite and endowed high solar absorptance (alpha) at 94.57% and solar thermal efficiency (eta) at 93.28%. The efficiency of remote and local photothermal-stimulated healing for micro scratches of the composite coating was as high as 95.08%. And the macroscopic damage repairing which was rarely reported can be about 100% by a novel photothermal patching method. Meanwhile, the composites also have behaviors of shape memory, reusability and ion transfer barrier performance. Overall, based on the advantages of facile preparation, cheap raw materials, high solar absorptance and solar thermal efficiency and excellent remote and local healing efficiency, the OCB/EV composite coatings have potential applications in solar energy harvesting and provides a new strategy for the local and contactless repair of polymeric coatings used in outdoor applications such as solar-energy collector, solar absorption systems and metal protection, especially for the repair of the macroscopic damage.