Deep-sea glass sponges-like hollow porous ceramic fiber aerogel part II: Polymer precursors, morphology and multiscale simulation

In the previous work, ceramic fiber aerogels with hollow porous structure imitating deep-sea glass sponge were reported firstly. The materials showed excellent thermal insulation and shrinkage resistance. However, the problems that have an impact on material properties had not been deeply investigated, for example, ceramic precursors and fiber surface pore structures. In this paper, different hollow porous ceramic fiber aerogels were prepared by using ceramic precursors. The mechanisms of hollow porous structures in terms of thermal and mechanical properties were investigated by means of multiscale simulations. The results indicated that the morphology and distribution of pores on the surfaces of fibers spun from various precursors exhibited significant variation. The pores on the surface of the fibers spun with polyborosilazane (PBSN) as the ceramic precursor had smaller and more uniformly dense pore sizes and were circular in shape. The thermal convection and thermal conduction were reduced by dense circular holes, and stress was effectively transferred and dispersed. The prepared hollow porous ceramic fiber aerogels displayed significantly improved thermal insulation, shrinkage resistance and mechanical properties.