Evolutionary Progress of Silica Aerogels and Their Classification Based on Composition: An Overview

Abstract

Aerogels are highly porous materials with fascinating properties prepared using sol-gel chemistry. Due to their unique physical and chemical properties, aerogels are recognized as potential candidates for diverse applications, including thermal insulation, sensor, environmental remediation, etc. Despite these applications, aerogels are not routinely found in our daily life because they are fragile and have highly limited scale-up productions. It remains extremely challenging to improve the mechanical properties of aerogels without adversely affecting their other properties. To boost the practical applications, it is necessary to develop efficient, low-cost methods to produce aerogels in a sustainable way. This comprehensive review surveys the progress in the development of aerogels and their classification based on the chemical composition of the network. Recent achievements in organic, inorganic, and hybrid materials and their outstanding physical properties are discussed. The major focus of this review lies in approaches that allow tailoring of aerogel properties to meet application-driven requirements. We begin with a brief discussion of the fundamental issues in silica aerogels and then proceed to provide an overview of the synthesis of organic and hybrid aerogels from various precursors. Organic aerogels show promising results with excellent mechanical strength, but there are still several issues that need further exploration. Finally, growing points and perspectives of the aerogel field are summarized.

An Updated Overview of Silica Aerogel-Based Nanomaterials

“…The selection of the precursor is an important step because it helps control the final properties of the material, leading to products with custom-made chemical and physical features. In general, silica aerogels can be divided into three classes acquired from pure silica, organically modified silicas (ORMOSILs), and organic–inorganic composite aerogels [ 13 ].…”

“… Classification of aerogels established on precursor composition. Created based on information from [ 9 , 11 , 12 , 13 , 14 ]. …”

Contribution of advanced windows and façades to buildings decarbonization: A comprehensive review

“…Lamy-Mendes et al (2021) provided a review on the production process of silica aerogels, and thermal and physical properties panels of blankets, cement, mortars, concrete, glazing systems, among others. Meti et al (2023) presented a review on the progress in the development of aerogels and their classification into three categories: inorganic, organic and organic-inorganic hybrid materials, Figure 22. Recent achievements in organic, inorganic, and hybrid materials and their outstanding physical properties were discussed focusing on adjusting the properties 2023) improved the building insulation using polycarbonate windows with nanogel.…”

“…Schematic of used glass system proposed by Zhang et al (2021)Figure22. Classification of aerogels on precursor composition(Meti et al, 2023)…”

Fabrication of Sn(IV)porphyrin-Imbedded Silica Aerogel Composite

“…Silica aerogels are the most widely used aerogels that consist of a three-dimensional network of connected silica nanoparticles. Because of their remarkable properties, such as high porosity, large surface area, ultralow bulk density, extremely low thermal conductivity, and high optical transparency in the visible region [3][4][5][6][7], they are useful for thermal insulation [8,9], catalysts [10,11], sensors [12,13], and environmental remediation [14]. Many of their properties exhibit scope for improvement and new functionalities through surface modification via the introduction of specific functional species [15].…”