Curvature-ordered biomimetic helical ceramic composite fiber aerogel with shrinkage resistance, thermal insulation properties, and mechanical properties

Ceramic aerogel with high porosity and low thermal conduction was widely used in the field of thermal insulation. However, shrinkage and structural damage were produced by the ceramic precursors during pyrolysis. The shrinkage and mechanical properties of ceramic aerogels required to be improved. Herein, inspired by spiral grass and passionflower, curvature-ordered ceramic fiber aerogels were prepared by electrostatic spinning combined with polymer-derived ceramics (PDCs) route. Shrinkage resistance properties, thermal insulation properties, and mechanical properties of ceramic fiber aerogels were investigated. The shrinkage resistance property of aerogels was improved by the tensile deformation of helical fibers during pyrolysis. The path of heat transfer was extended through the helical fibers and heat conduction was reduced. The gas was confined in a porous network formed by helical fibers that lapped over each other, and thermal convection was minimized. Thermal radiation was attenuated due to reflection and scattering at the core-shell interface of the helical fibers. The mechanical properties of the aerogel were enhanced by the helical structure of the fibers and the stress diffusion mechanism. The tensile and compressive properties of the spiral ceramic aerogel were improved through the curvature structure by about 6 MPa and 3 MPa, respectively. The results showed that the helical ceramic composite fiber aerogel with ordered curvature exhibited shrinkage resistance, thermal insulation, and mechanical properties.