Tailoring hydrophobicity and dispersibility of silica aerogels via surface modification with silane coupling agents

SiO 2 aerogel serves as an attractive functional filler for thermal insulation coatings, yet its agglomeration compromises dispersibility and performance. To enhance dispersibility and hydrophilicity, SiO 2 aerogel was chemically modified with three silane coupling agents at mass fractions of 2.5% and 5.0%. FTIR analysis confirmed strengthened hydroxyl group (-OH) stretching vibration peaks (3200–3700 cm -1 ) in modified samples, suggesting the introduction of hydrophilic groups. Contact angle measurements demonstrated that the KH570-5% modified sample exhibited the lowest contact angle (62.7° compared with 143.7° for the unmodified sample), indicating significantly improved hydrophilicity. SEM observations revealed improved dispersion uniformity, particularly at higher dosages. The modification reduced agglomeration to varying degrees, with the KH570-5% treatment yielding optimal dispersibility and hydrophilicity.