Wrinkled-porous core-shell SiO2 aerogel fiber composites for thermal insulation coatings: Strain energy storage, unidirectional gas channels, and water resistance

Although SiO 2 aerogels have broad application prospects in the field of thermal insulation coatings, their fragile structure is easily collapsed and damaged due to capillary forces during preparation and coating processes. While surface hydrophobic treatment can alleviate this damage to some extent, it simultaneously reduces the compatibility of the aerogel with the coating matrix, hindering its uniform dispersion in the system, thus creating a contradiction. Here, we introduced wrinkled-porous core-shell SiO 2 aerogel fiber composites (WP-PLA/CA-SiO 2 ), fabricated via electrospinning using polylactic acid (PLA) and cellulose acetate (CA) as shell materials and SiO 2 sol as the core precursor. Thermal insulation coatings were prepared based on these fibers. The robust outer shell of the fibers effectively protected the internal aerogel from damage caused by capillary forces during the preparation and application of coatings. Crucially, the surface pores on the shell served as unidirectional channels, facilitating the release of internal gases during the drying process while effectively preventing the entry of external moisture. Simultaneously, the wrinkled fiber morphology functioned as a strain energy storage device, offsetting internal drying stress by releasing the stored strain. This synergistic triple-action mechanism ensured that the aerogel fibers maintained excellent structural integrity and were relatively uniformly dispersed within the coating matrix. As a result, the coating exhibited superior thermal insulation performance (with a maximum surface temperature of only ∼45 °C after 60 min of heating) and excellent storage stability (>6 months). This work provides a transformative strategy to overcome the key obstacles hindering the application of aerogels in the coatings field.