Effect of molar concentration and drying methodologies on monodispersed silica sol for synthesis of silica aerogels with temperature-resistant characteristics

A variety of hierarchical nanoporous silica aerogels with diversified particle distributions were synthesized from well-dispersed silica sols by a traditional sol-gel method. Among the six particle sizes of aerogels, the silica aerogel with 0.4 M TEOS/MTMS surface modification and supercritical drying attains 11.61 +/- 2.96 nm constituent part with well slender size particle dissemination, high-temperature confrontation and low thermal conductivity. In association with the outmoded two-step acid-base dilution of silica sols, the well-diffused form of silica sols with surface alteration also provides a low thermal conductivity of 0.01865 W.m- 1 K-1 with greater thermal resistance. In addition, the drying shrinkage can be minimized with surface modification by properly silylation with TMCS. The concentrations of well-diffused silica sol were adjusted to achieve higher surface area, low density, large pore size and structure, and temperature resilience with the help of controlling the sol-gel reaction. The resilient skeleton structure developed from the assembly of tiny particles can efficiently restrict the glutinous heat dissipation between aerogel networks without collapsing a porous network up to a higher temperature of 900 degrees C. However, this network retains a similar pattern up to 1000 degrees C with only 32 % volume contraction after 2hr of heat treatments. At an elevated temperature of 1100-1200 degrees C, the viscid heat flow between nanoparticles and the porous network cannot be meritoriously suppressed and starts to collapse after a shorter duration. The enormous results of silica aerogels will help design suitable thermal insulation with higher resilience and low thermal conductivity.