Phase Change Materials (PCMs) are substances that absorb or release thermal energy during phase transitions, such as melting or freezing. They can store heat when they change from solid to liquid and release it when they solidify. This property makes them useful for temperature regulation in various applications, including building materials and thermal energy storage systems. PCMs are commonly used in energy-efficient buildings to maintain comfortable indoor temperatures. By integrating PCMs into walls or ceilings, they can help reduce heating and cooling costs. Additionally, they are utilized in packaging to keep perishable goods at stable temperatures during transport.