Polymer/phase change material (PCM) hybrid systems are innovative composite structures developed to enhance the performance of thermal energy storage technologies. Although PCMs can store large amounts of energy at low temperature differences due to their high latent heat capacity, they suffer from several limitations such as low thermal conductivity, phase leakage during melting, cyclic instability, and volumetric changes. Polymer matrices address these limitations by maintaining the structural integrity of PCMs, preventing leakage during the melting phase, and improving the mechanical stability of the hybrid system. Furthermore, the incorporation of nanofillers increases the thermal conductivity of the composites, thereby improving heat transfer efficiency and expanding the potential application areas of these materials.

This study presents the fundamental design strategies of polymer/PCM hybrid systems, including microencapsulation, composite fabrication techniques, porous matrix impregnation, and form-stable PCM formulations. The thermal performance of the hybrid systems was evaluated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermal conductivity measurements, thermal cycling tests, and thermal imaging methods. The results demonstrate that appropriate polymer selection and optimized nanofiller integration can yield hybrid systems with high energy storage capacity, enhanced thermal stability, and long-term cycling durability.

Polymer/PCM hybrid systems have a wide range of applications, including passive thermal regulation in buildings, thermal management of electronic devices, temperature control in lithium-ion batteries, solar energy systems, smart textiles, and cold-chain logistics. In this context, these hybrid materials provide significant potential for improving energy efficiency and advancing sustainable material technologies.