Nonwoven mats were fabricated from a polyvinylidene fluoride (PVDF)/polyethylene glycol 1000 Da (PEG 1000) blend by the electrospinning process. PEG 1000 is a low-temperature phase change material that acts as a heat storage material, while PVDF serves as a supporting material to afford a mechanically strong form-stable structure. Addition of fumed silica to electrospun (e-spun) PVDF/PEG 1000 nanofibers helped prevent the leakage of molten PEG 1000 during the solid-liquid phase change, as confirmed by field emission scanning electron microscopy. It was also found that the addition of fumed silica helps improve the mechanical strength of the PVDF/PEG 1000 nonwoven mats. The thermal properties of PVDF/PEG 1000 and PVDF/PEG 1000/fumed silica composite nonwoven mats were investigated by differential scanning calorimetry. There were no significant changes in the melting temperature and heat of fusion of PEG 1000 after 100 heating/cooling cycles, thereby confirming that these nonwoven mats have high thermal stability. The fumed-silica-incorporated PVDF/PEG 1000 nonwoven mats had large energy storage capacity and excellent mechanical strength. Hence, the aforementioned types of mats are thought to have various applications in energy storage and in the manufacture of thermoregulating textiles. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 35963603, 2011