Low-cost, superhydrophobic, flame-retardant sunflower straw-based xerogel as thermal insulation materials for energy-efficient buildings

Low cost, low energy consumption, and environment-friendly novel thermal insulation materials are highly attractive for energy-efficient buildings. However, traditional petroleum-based foams and aerogel require complicated processing, high cost, and non-degradability, which limit their sustainable development and application. Herein, multifunctional robust sunflower straw-based xerogels as thermal insulation materials are fabricated by simply filtrating and drying under ambient pressure without any extraction processing, due to sunflower straw raw materials with high content of cellulose. With the addition of KH550 and SiO2 nanoparticles, the obtained sunflower straw-based xerogels exhibit excellent thermal insulation (0.0469 W/(mK)), superior superhydrophobicity (water contact angle (WCA) = 153.2°), remarkable fire resistance, high mechanical property. These advanced properties make it an ideal thermally insulation material for diversified applications in harsh environments.