Binary surfactant-optimized silica aerogel slurries for building materials: Effects of formulation and content

Developing silica aerogel slurries is a strategic approach for incorporating silica aerogels into matrix materials to enhance the efficiency of aerogel composites. This study introduces a novel binary surfactant mixture, using a 1:4 ratio of polyether L62 and CTAC, optimized for the performance of aerogel slurries. Our extensive testing reveals that this formulation significantly reduces the surface tension to 24.25 mN/m and achieves a remarkable thermal conductivity of 26.7 mW/m/K, while maintaining high hydrophobicity with a contact angle exceeding 125°. The slurries exhibit a wet density of 0.48 g/cm³ and a dry density of 0.098 g/cm³, emphasizing the lightweight nature of the aerogel composites. Additionally, the study illustrates that while increasing the surfactant concentration optimally raises the aerogel content, excess surfactant adversely affects the thermal insulation properties. Microstructural analysis confirms that the binary surfactant mixture effectively modifies the aerogel surface, overcoming the dispersal limitations associated with aerogel's hydrophobic groups. This breakthrough in slurry formulation greatly enhances both the insulating and water-repellent capabilities of silica aerogels, offering a viable engineering solution for developing high-performance aerogel composites for thermal insulation applications.