Optimized preparation of thermal insulation hydrophobic SiO2 aerogel based on orthogonal design method

Springback effect of ambient-pressure-dried silica aerogels: nanoscopic effects of silylation revealed by in situ synchrotron X-ray scattering

“…1 While metal, 2 organic, 3,4 ceramic or composite aerogels are known; 5–8 silica aerogels remain the most studied system, making it worthwhile to explore the fundamentals of the aerogel formation and structure. 6,9–11 Furthermore, the preceding sol–gel process allows for tailoring many of the properties of this inorganic porous network, such as the bulk density, and the size of the elementary particles. 12…”

“…1 While metal, 2 organic, 3,4 ceramic or composite aerogels are known; [5][6][7][8] silica aerogels remain the most studied system, making it worthwhile to explore the fundamentals of the aerogel formation and structure. 6,[9][10][11] Furthermore, the preceding sol-gel process allows for tailoring many of the properties of this inorganic porous network, such as the bulk density, and the size of the elementary particles. 12 Since a material may only be called an aerogel if the gel network experiences minor or no volume changes during drying, 13 specic precautions must be taken to minimize the shrinkage of the material.…”

Nanoporous Silica–Chitosan Aerogels for Thermal Insulation and Flame Retardancy

“…23 However, the cost of producing conventional SA is prohibitively high due to expensive raw materials and the specialized equipment as well as technologies. For example, the traditional silicon sources for preparing SA are mainly methyl orthosilicate 24 and ethyl orthosilicate, 25 which are not only costly but also possess toxicity concerns. Furthermore, the conventional drying method of SA is supercritical drying, 26 which suffers from drawbacks such as prolonged duration, excessive energy consumption, and poor safety.…”

In Operando μCT Imaging of Silylated Silica Aerogels during Ambient Pressure Drying and Spring-Back

“…The surface modification alleviates condensation reactions by introducing functional groups, making drying shrinkage reversible. Several silylating agents are reported in the literature, such as trimethylchlorosilane (TMCS). − This reversible shrinkage in modified gels is known as the spring-back effect (SBE).…”

“…Despite being a well-known phenomenon in the production of aerogels by APD, little is known about the physical mechanisms and related material structure evolution at the nanoscale behind the spring-back effect. Only few studies have tackled the conditions of its emergence and result in structural and compositional changes, while the impact of the synthesis, aging, surface modification, and drying on the spring-back efficiency has been exhaustively studied. ,,,,− The reversible shrinkage inherent to the SBE in silylated silica aerogels unveils fundamental research questions on the deformability of porous ceramic materials, and a better understanding of the SBE may give insights for improving the production of aerogels by APD. However, it is difficult to quantitatively track structural and compositional variations during drying as it generally requires a controlled environment under ambient conditions and the use of non-destructive methods.…”