Phase change composite fiber membranes based on polyurethane/ polyethylene glycol/silica with super-wetting and photothermal properties

Phase change materials (PCMs) temperature regulation by absorbing or releasing heat. Meanwhile, silicon dioxide nanoparticles (SiO2 NPs) can effectively increase the reflectance of visible and near-infrared light, lowering the surface temperature of fibers. In this study, electrospinning technology was employed to fabricate polyurethane/polyethylene glycol (PU/PEG) fiber membranes, which were made with PEG serving as thermal energy storage material and PU acting as a mechanically strong supporting material. Then, a layer of SiO2 NPs was electrosprayed onto the surface of phase change fibers, finally creating a composite fiber membrane with superwettability and a photothermal regulating function. The results showed that, although the static WCA of PU/PEG/SiO2 fiber membrane reached around 115.4 degrees, liquid water droplets (100 mu L) slowly penetrated into the fiber membrane and the penetrating velocity was faster than that of a hydrophilic PU/PEG membrane. The melting enthalpy (Delta Hm) of the fiber membrane could be kept at 86.30 J/g when the loading amount of PEG was 1.25 times that of the PU. The phase change fiber membrane's variations in the Delta Hm and crystallization enthalpy (Delta Hc) after 100 heating-cooling cycles were less than 5 %, indicating its great thermal stability. Through the introduction of hydrophilic SiO2 NPs, the average reflectance of PU/PEG/SiO2 fiber membranes in visible and near-infrared light at 500-1250 nm was increased to 85.17 %. After 40 min of xenon lamp irradiation, the surface temperature of PU/PEG/SiO2 fiber membranes was 4.19 degrees C lower than that of fibers without SiO2 NPs, demonstrating its effective cooling ability. This work proposes an effective strategy for preparing intelligent textiles with features, such as quick drying, infrared stealth and refrigeration capabilities.