# Advanced Micro/Nanocapsules for Self-Healing Coatings
## 5 Types of Self-Healing Capsules
The concept of self-healing coatings inspired by biological systems is rooted in the idea of mimicking the regenerative capabilities found in living organisms, enabling materials to repair physical damage autonomously. The introduction of biological self-healing capsules into coatings has opened up new possibilities for enhancing durability and functionality in various industrial applications by harnessing the power of nature for self-repair [75]. The mechanism of action behind biological self-healing capsules involves a carefully orchestrated process that triggers the release of healing agents upon detecting damage in the coating [71]. These capsules are designed to respond to specific stimuli, such as changes in pH or temperature, which are indicative of damage or corrosion. Once the capsules rupture or degrade in response to the stimuli, the self-healing agents are released, filling in cracks or gaps in the coating to restore its integrity. This self-healing process not only repairs the visible damage but also helps prevent further deterioration, prolonging the lifespan of the coating and reducing maintenance requirements in various applications. Examples of biological self-healing capsules include micro/nanocapsules fabricated using  
Figure 4: The classification of self-healing capsules. different types of micro/nanocontainers. These capsules can be loaded with a variety of self-healing agents, such as polymers, resins, or other active materials capable of repairing damage in coatings. The incorporation of biological self-healing capsules into coatings has been shown to enhance their anti-corrosion properties and improve overall performance in harsh environments. By leveraging the versatility and efficacy of these innovative capsules, researchers and engineers are advancing the field of self-healing coatings, paving the way for more durable and sustainable materials in various industries. Physical self-healing capsules are innovative materials that play a crucial role in the development of self-healing coatings. These capsules are designed to contain healing agents that can be released when damage occurs, promoting the repair of the coating without human intervention. The concept of physical self-healing capsules is inspired by biological systems that possess the remarkable ability to repair themselves in response to damage. By incorporating these capsules into coatings, researchers aim to enhance the durability and longevity of various materials, ranging from automotive paints to protective coatings for infrastructure. The mechanism of action of physical self-healing capsules involves a proactive response to damage, triggered by external stimuli such as mechanical stress or environmental factors. When a coating containing these capsules experiences a crack or scratch, the capsules rupture, releasing the healing agent into the damaged area. The healing agent then interacts with the surrounding material, catalyzing a self-repair process that restores the integrity and functionality of the coating. This autonomous healing process demonstrates the potential of physical self-healing capsules to revolutionize the field of protective coatings and materials engineering.