Hierarchical SiO2@Bi2O3 core/shell electrospun fibers for infrared stealth camouflage

Abstract

Novel, freestanding membranes composed of SiO₂@Bi₂O₃ hierarchical core/shell fibers were prepared by a combination of two fabrication methods: electrospinning and hydrothermal reaction. The SiO₂@Bi₂O₃ composite membranes were primarily supported by flexible SiO₂ fibers after the calcination treatment of electrospun PVA/SiO₂ hybrid fibrous membranes. SiO₂@Bi₂O₃ composite fibers were fabricated via a process that entails hydrothermal growth of a bismuth precursor nanocoating (Bi-PN) on the surface of SiO₂ fibers followed by the thermal treatment of the harvested SiO₂@Bi-PN fibers. It was observed that Bi₂O₃ nanoparticles were well anchored on the surface of SiO₂ fibers and the phase transition of Bi₂O₃ nanoparticles occurred during the thermal treatment of SiO₂@Bi-PN composite fibers at different temperatures. The infrared emission rates of the resultant SiO₂@Bi₂O₃ composite membranes were evaluated in comparison with pure SiO₂ fibers in 2–22 μm wavebands. It is theorized that the coating of Bi₂O₃ nanoparticles contributes to the decrease of infrared emissivity, and the infrared emission properties of SiO₂@Bi₂O₃ composite fibers are related to the α-Bi₂O₃ phase. The results favourably indicated prospects of SiO₂@Bi₂O₃ composite fibrous membranes for applications in infrared stealth camouflage.