UV-assisted stabilization of superhydrophobic nanofibrous membranes for waterproof, breathable and thermal insulation applications

Polyacrylonitrile (PAN)/polyurethane (PU)/hydrophobic silicon dioxide (SiO2) nanofibrous membranes were prepared by electrospinning combined with a UV-induced stabilization method. The PAN/PU/SiO2 membranes possessed excellent self-cleaning performance because the introduction of SiO2 nanoparticles endowed the nanofibrous membranes with high surface roughness and good hydrophobicity. In addition, SiO2 nanoparticles could also promote the waterproof performance of nanofibrous membranes because hydrophobicity improved and pore size decreased with the increase of SiO2 content. Water vapor transmission rate of the membranes decreased from 10.8 to 9.2 kg m−2 d−1 with increasing of SiO2 concentration because SiO2 nanoparticles could fill the spaces among the adjacent nanofibers. Reflectance to sunlight of the PAN/PU/SiO2 membrane was much higher than that of the PAN/PU membrane, indicating an obvious radiative cooling effect due to loading of SiO2 nanoparticles. This facile fabrication of fluorine-free superhydrophobic membranes provides advantages for potential applications in self-cleaning materials and versatile protective clothing.