Optimized Design and Fabrication of Polyethylene Glycol 1000/Polyamide 6 (PEG1000/PA6) Nanofibers for Phase Change Materials (PCMs) Application

Ultrafine phase change nanofibers based on polyethylene glycol 1000 (PEG1000) as phase change material (PCM) and polyamide 6 (PA6) as a supporting material were prepared in a systematic manner planned by the Design-Expert® software using the uniaxial electros-pinning. Research surface methodology (RSM) was carried out to optimize the parameters and conditions leading to minimize the fiber diameter. The effect of PEG content, applied voltage, needle gauge, and flow rate on the fiber characteristics was studied by a central composite design (CCD). The minimum diameter of nanofibers was predicted by a quadratic model to be 64.33 nm and the actual fibers diameter prepared under optimal condition showed a very low relative standard error (RSE). It was shown that the PEG/PA6 mass ratio has the dominant effect on the fibers diameter. The results from FTIR and FE-SEM images confirmed well encapsulated PEG in PA6 and no leakage and morphology alterations were observed after heating tests. To further investigate morphological structure and the quality of PEG1000 encapsulation in PA6 matrices, the composite fibers underwent a solvent treatment using ethanol. The results proposed a new innovative method to control operational electrospinning conditions for encapsulating phase change materials in polymer matrices which is very important in thermal energy saving/retrieving applications.