Super-insulating properties of porous ceramic particles fabricated by a self-assembly process using complex fluids

Porous silica particles were synthesized by an emulsion-assisted self-assembly process. The templating materials, polymeric nanospheres or block copolymers, were self-organized with the precursor inside emulsions to prepare porous ceramic particles after calcination. The thermal insulating properties of mesoporous, macroporous, and meso-macroporous particles were compared by measuring their thermal diffusivity using a laser flash apparatus. The insulating properties of the porous particles could be controlled by changing the emulsification conditions using a rotating cylinder instead of a conventional homogenizer to induce a hollow interior structure of the porous particles. The lowest value of the thermal conductivity was recorded as roughly 10 mW/mK for the meso-macroporous particles, which is comparable to previous materials including aerogels. The porous ceramic particles additionally can be applied as coating materials for superhydrophobic surfaces via a lotus effect.