Animal-skin-inspired SiO2 aerogel composite fibers featuring molecular chain entanglement and size-selective permeation of liquid moisture/steam for thermal insulation coatings

SiO 2 aerogels have drawn significant attention for waterborne thermal-insulation coatings in buildings owing to their excellent properties: low density, high porosity, and ultra-low thermal conductivity. However, their practical use is hampered by structural collapse upon direct exposure to coating solvents, leading to a notable loss of thermal insulation performance. To overcome this challenge, we proposed a bioinspired shell-protection strategy by constructing SiO 2 aerogel@PMMA core-shell fibers via coaxial electrospinning. The PMMA shell, inspired by animal epidermis, provided size-selective permeability: it blocked liquid penetration during waterborne coating preparation while allowing steam escape during drying of SiO 2 aerogel core layer. Meanwhile, mimicking the dermis of animal skin, the entangled molecular chains in PMMA shell dynamically resisted internal gas-expansion stress during the drying, maintaining structural integrity. The resulting fibers exhibited excellent mechanical and thermal insulation performance, with respective values of 35.47 MPa and 0.043 W/m·K, respectively. Furthermore, the prepared coatings also presented exceptional mechanical and thermal insulation properties, with respective values of 13 MPa and 0.059 W/m·K. This work will provide a new and effective pathway for SiO 2 aerogels to remain stable and fully exert their thermal insulation efficacy in building coatings.