The ultrafine composite fibers consisting of lauric acid (LA). polyethylene terephthalate (PET), and silica nanoparticles (nano-SiO2) were prepared through the materials processing technique of electrospinning as an innovative type of form-stable phase change materials (PCMs). The effects of nano-SiO2 on morphology, thermal energy storage, thermal stability, and combustion properties of electrospun LA/PET/SiO2 composite fibers were studied. SEM images revealed that the LA/PET/SiO2 composite fibers with nano-SiO2 possessed desired morphologies with reduced average fiber diameters as compared to the LA/PET fibers without nano-SiO2. DSC measurements indicated that the amount of nano-SiO2 in the fibers had an influence on the crystallization of LA. and played an important role on the heat enthalpies of the composite fibers; while it had no appreciable effect on the phase change temperatures. TGA results suggested that the incorporation of nano-SiO2 increased the onset thermal degradation temperature, maximum weight loss temperature, and charred residue at 700 degrees C of the composite fibers, indicating the improved thermal stability of the fibers. MCC tests showed that the heat resistance effect and/or barrier property generated by nano-SiO2 resulted in an increase of initial combustion temperature and a decrease of the heat release rate for the electrospun ultrafine composite fibers. (c) 2011 Elsevier Ltd. All rights reserved.