Silica aerogels: from materials research to industrial applications

Abstract

Silica aerogels are advanced materials with outstanding properties, including high specific surface area and porosity, low thermal conductivity, density, dielectric constant, and refractive index. However, the excellent properties of silica aerogels have shown limited utility in industrial applications, primarily as thermal insulation materials, where they hold only a small (1.1-2.6%) market share. The emergence of clean energy technologies stimulated renewed interest in silica and other aerogels. Here the recent advances in the production and applications of silica aerogels are summarized, and the current challenges and future development opportunities are discussed. The conventional and emerging syntheses and characterization methods of silica aerogels are introduced, followed by a discussion on thermophysical properties and potential applications. The fabrication processes of silica aerogels are analysed at different industry development stages. Recent advances in aerogels research are considered, highlighting the obstacles and possible solutions for the successful translation and industry uptake and focusing on the emerging applications in electric vehicles and building insulation.

Nanoporous Silica–Chitosan Aerogels for Thermal Insulation and Flame Retardancy

“…Aerogel is a fascinating solid material with a range of unique characteristics. Typically, aerogel is prepared by a sol–gel process . Colloidal solid particles are dispersed in a liquid to form a sol, which is then transformed into a sponge-like three-dimensional (3D) network to form a gel, where the pores are filled with liquid.…”

“…Typically, aerogel is prepared by a sol−gel process. 10 Colloidal solid particles are dispersed in a liquid to form a sol, which is then transformed into a sponge-like threedimensional (3D) network to form a gel, where the pores are filled with liquid. Then, through the corresponding drying steps, an excellent performance aerogel is cast.…”

Preparation and property of PVA-based colorful coating composite reinforced with silica aerogel particles filled by high-loaded flame retardant

“…Silica aerogel is assigned to ordered mesoporous material supported by connected silica backbone at the nanoscale. This structure solely formed by Si-O-Si bonds, leads to the expansion of pore volume, the extension of a three-dimensional (3D) branched and circuitous network, "blind alley" ba e of thermal transport, and delay of non-resonant sound transmission, which is labelled by idiosyncratic properties as low density (0.003-0.5 g/cm 3 ), large porosity (80-99.8%), low thermal conductivity (0.005-0.1 W/(m•K)), ultra-low dielectric constant (k = 1.0-2.0), and a low refractive index (1.05) [11,[13][14][15][16][17]]. These properties above offer a great potential market for silica aerogel in thermal insulation, acoustics, environmental remediation, catalysis, optics, and energetic particle detectors.…”

Resorcinol Formaldehyde Aerogels Modified with Graphene for the Removal of Minocycline Antibiotics from Aqueous Solutions: Mechanisms and Influencing Factors

“…They have unique characteristics, such as low heat conductivity and large speci c surface area. They are suitable for speci c constructional, electrical, medical, and environmental applications because of their unique properties [23,24]. A novel class of integrated aerogels may now be synthesized thanks to organic precursors that can create stable covalently linked (C-C) organic polymers [25].…”