TiO₂/SiO₂ spiral crimped Janus fibers engineered for stretchable ceramic membranes with high-temperature resistance

The tensile brittleness of ceramic nanofibrous materials makes them unable to withstand the relatively large fracture strain, greatly limiting their applications in extreme environments such as high or ultra-low temperatures. Herein, highly stretchable and elastic ceramic nanofibrous membranes composed of titanium dioxide/silicon dioxide (TiO₂/SiO₂) bicomponent spiral crimped Janus fibers were designed and synthesized via conjugate electrospinning combined with calcination treatment. Owing to the opposite charges attached, the two fibers assembled side by side to form a Janus structure. Interestingly, radial shrinkage differences existed on the two sides of the TiO₂/SiO₂ composite nanofibers, constructing a helical crimp structure along the fiber axis. The special configuration effectively improves the stretchability of TiO₂/SiO₂ ceramic nanofibrous membranes, with up to 70.59% elongation at break, excellent resilience at 20% tensile strain and plastic deformation of only 3.48% after 100 cycles. Additionally, the relatively fluffy ceramic membranes constructed from spiral crimped Janus fibers delivered a lower thermal conductivity of 0.0317 W m^-1 K^-1, attributed to the increased internal still air content. This work not only reveals the attractive tensile mechanism of ceramic membranes arising from the highly curly nanofibers, but also proposes an effective strategy to make the ceramic materials withstand the complex dynamic strain in extreme temperature environments (from -196 °C to 1300 °C).