Preparation of novel form–stable composite phase change materials with porous silica nanofibrous mats for thermal storage/retrieval

Abstract

Electrospun SiO2 nanofibrous mats have been widely utilized as substrate of form-stable phase change materials due to large specific surface area and high convection coefficient. In order to overcome the brittleness and enhance the absorption capacity of SiO2 nanofibrous mats as substrate, flexible and hollow SiO2 nanofibrous mats were prepared by single-spinneret electrospinning which eliminated complicated spinneret and unstable structure compared with coaxial electrospinning. Quinary fatty acid eutectics were chosen as representative fatty acid which were adsorbed in SiO2 nanofibrous mats to form form-stable phase change materials. The results showed that hollow structure can be observed as the content of paraffin oil decreased from 1.67 to 0.70 g, and as-prepared hollow nanofibrous mats displayed favorable flexibility. DSC results demonstrated that the largest melting/crystallization enthalpy supported by hollow SiO2 nanofibrous mats was approximately 123.80/120.50 J g−1, which was much higher than solid SiO2 nanofibers. More importantly, after 30 cycles, there was no obvious change for phase change temperature and enthalpy. The thermal conductivity of representative form-stable phase change materials was over three times than that of quinary fatty acid eutectics. Hence, flexible and hollow SiO2 nanofibrous mats were excellent substrate in form-stable phase change materials and would have wide application prospects.