Superelastic Carbon Aerogels: An Emerging Material for Advanced Thermal Protection in Extreme Environments

Abstract

speed airflow scouring. Accordingly, the thermal protection system (TPS) must be applied on their surface to cope with the integrated heat load accumulated during flight. [2] The lightweight nature of TPS is critical in addressing the criteria for ultralong-range combat military weapons with high sound speeds and load capacities while considering the production cost in check. Kistler of Stanford University first proposed the concept of aerogel in 1931, [3] which was fabricated by exchanging the liquid in a wet gel by gas whilst guaranteeing that the internal structure did not collapse, becoming one of the lightest solid materials known to date. The abundance of internal nanoscale pore size and highly tortuous pore structure determine aerogel's excellent thermally insulation performance, with the thermal conductivity as low as 0.005 W m −1 K −1 . [4] NASA pioneered the use of aerogels as efficient insulating materials on several Mars rovers and spacecraft parts, such as the insulation assembly of Rover Mars batteries, the outer surface of vehicle decelerators, [5] etc., and is also advancing their application in extra-vehicular insulating suits. [6] Oxide ceramic aerogels have currently been the most rapidly developed in high-temperature insulation; however, due to the restrictions of crystallization-induced pulverization, large thermal expansion, and relatively low operating temperatures, for example, SiO 2 (650 °C), [7] ZrO 2 (1100 °C), [8] Al 2 O 3 (1300 °C), [9] and mullite (1400 °C), these aerogels and their composites suffer from severe strength deterioration and catastrophic structural failure during significant temperature gradient changes or long-term high-temperature exposure. [10] Conversely, carbon aerogels (CAs) maintain their mesoporous structure despite heat treatment over 2500 °C under a vacuum or inert atmosphere, showing favorable thermal stability at ultra-high temperatures. [11] In addition, they also have a much higher specific extinction coefficient (190 m 2 kg −1 ) than others (e.g., SiO 2 aerogel with 20 m 2 kg −1 ), which leads to lower radiative thermal conductivities. [12] Therefore, CAs are anticipated to be up-and-coming candidates for the TPS of hypersonic vehicles in conditions of severe heat flow density and ultra-high temperatures.The terms of CAs initially referred to carbonaceous substances that exist as 3D monoliths macroscopically and

Woven Agarose–Cellulose Composite Aerogel Fibers with Outstanding Radial Elasticity for Personal Thermal Management

“…For practical applications, aerogel fibers must possess excellent radial elasticity. 54 In particular, if aerogel fibers are woven into textiles for use in clothing, they must rebound effectively under external extrusion forces to prevent the pore structure from becoming dense, which will reduce the thermal insulation performance. The ATAFs without hydrophobic modification were inelastic and underwent irreversible deformation when compressed, owing to the flexible AG gel skeleton.…”

Electrospun Nanofiber Materials for Photothermal Interfacial Evaporation

“…In contrast to other innovative production methods for membranes, electrospinning has many advantages. First, electrospinning can convert many soluble polymers into fibrous films [ 31 ]. Second, by adjusting the solution concentration, voltage, distance, and other variables, the electrospinning can change the structure and shape of the fiber membrane [ 32 ].…”

Superhydrophobic Carbon Aerogel Derived from Edible-Sugar for Removal of Oils and Nitro Aromatics

“…28,29 Recently, three-dimensional carbon-based aerogels (CAs) have been in high demand because of their 3D architecture, high porosity, low density, elasticity, high mechanical and chemical stability, and better absorption capabilities. 30−33 CA has already been known for numerous other applications such as thermal insulation, 34,35 sound and shock absorption, 36 wastewater treatment, 37 sensing, 38,39 and adsorption capabilities. 40,41 Few reports are available considering their use in oil−water separation applications.…”

“…Many attempts have been made to fabricate the material with a high oil–water separation efficiency or absorption capacity. Among them, carbon-based materials, nanomaterials, , and nanocomposites − are widely been used for multiple applications including the absorption purposes. , Recently, three-dimensional carbon-based aerogels (CAs) have been in high demand because of their 3D architecture, high porosity, low density, elasticity, high mechanical and chemical stability, and better absorption capabilities. − CA has already been known for numerous other applications such as thermal insulation, , sound and shock absorption, wastewater treatment, sensing, , and adsorption capabilities. , Few reports are available considering their use in oil–water separation applications. Huang et al have synthesized biobased aerogel by taking raw materials such as bamboo powder, graphene oxide (GO), and waste paper, Dai et al have synthesized graphene aerogel (GA) using carbon nanotubes (CNTs), cellulose, and lignin as additives, Li et al have used pomelo peel and reduced graphene oxide (r-GO) as precursors of CA, and Yang et al have synthesized aerogel by taking sodium alginate, GO, and silicon oxide .…”