Influence of Hydrophilic and Hydrophobic modification of the porous matrix on the thermal performance of form stable phase change materials: A review

Solar radiation, being an ample source of renewable energy can be captured and stored in the form of latent heat using phase change materials (PCM) to make the environment sustainable. Furthermore, form stable phase change materials (FSPCM) are preferred due to their light weight and desirable thermal characteristics such as higher thermal conductivity, molten PCM holding capacity etc. In this regard, a porous matrix is utilized as a support to hold PCM. A thorough investigation on mechanism and methods of hydrophilic and hydrophobic modification of the porous medium has been carried out in this review paper. Water contact angle (WCA) is an influential parameter that governs hydrophilicity/hydrophobicity. Modified hydrophilic surfaces accept a wide range of aqueous solutions with increased chemical resistance while hydrophobically modified surfaces are self-cleaning and anti-corrosive. Moreover, reversible transition of wetting state can be attained in carbon-based materials like graphene, polycarbonate etc., which helps to prevent leakage and accomplish superior impregnation of PCM. The influence of hydrophilic and hydrophobic modification of the porous matrix on the thermal performance of the FSPCM and their applications have been deliberated in this review as per the available scientific literatures.