In an effort to mimic self-healing functions in biological systems, we report here the development of polymeric coating systems that are stimuli responsive and possess the ability to self-heal when damaged. The aim is to design and develop coatings with enhanced durability and performance. This work describes coatings that contain small amounts of healing agent in the form of microcapsule homogeneously dispersed in the coating medium. The most attractive feature of this system is that the factors that cause the most damage to the coating, such as humidity, mechanical compromise, exposure to high temperatures etc., are the same factors that initiate self-healing phenomenon. This property is unique since the extent of the healing is proportional to the magnitude of the damage, i.e., repair on demand. It was confirmed that the simulated natural aging or mechanical damage triggered the release of healing agents, repaired the damage, restored the integrity of the coating and enhanced overall coating properties. Observations in current investigation showed that at early stages of accelerated weathering, the self-healing samples resisted the degradation process as compared to control coatings. The self-healing performance was assessed through direct evaluation and observation of improved key coating properties such as, enhanced mechanical and surface properties. The self-healing samples showed several fold enhancements in corrosion resistance as well as reduced water vapor permeability as compared to standard polyurethane coatings. The development of self-healing materials has the potential to significantly impact the coatings and related industries by enhancing coatings' performance and service life.
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