Aerogel
Description
Any synthetic, open-celled solid foam that is composed of a network of interconnected nanostructures. Aerogels are derived from gels in which the liquid has been replaced with gas while retaining the structure of the solid framework. The first aerogel material was created the Samuel Kistler in 1931 using silica gel (patented 1937). The unique properties of aerogels are due to its high surface area and open porous structure that provides extremely low density, as well as low thermal and sound conductivities. Although aerogels may feel fragile to the touch, they have strong structural integrity. They have been used in solar cells, fuel cells, batteries, supercapacitors as well as more mundane things such as paints, cosmetics, coats, rugs, pipes, spill-clean-up kits and insulation. Of particular interest for museums is the aerogels extrodinary ability to minimize heat transfer when used in fire protection blankets (Praestegaard 2023).
Aerogels were first, and most commonly, made from silica (see Aerogel, silica), but they are also been made from:
- Natural polymers: Cellulose, Agar (SEAgel), Gelatin, Pectin
- Synthetic polymers: phenol-formaldehyde, Polyacrylate, Polystyrene, Polyurethane, Epoxy, Polyimide (AeroZero)
- Metal oxides: iron oxide, Tin oxide, lanthanide, actinide
- Carbon: carbon nanotubes
- Metals: Gold, Copper
Synonyms and Related Terms
aerogel; air glass; frozen smoke; blue smoke; solid air; solid cloud
Brand names: Santocel (obsolete); Pyrogel; Nanogel; Cryogel; Spaceloft; AeroZero
Applications
- Fire protection
- Thermal and sound insulation
- Thickening agent
- Collection of dust in outer space
Risks
- Structurally strong but can shatter like glass
- Will dissolve in water unless chemically treated
Physical and Chemical Properties
- Particle size averages 2-5 nm
- Surface area: up to 1200 m2/g
- Pore size is usually 100nm
- Porosity greater than 50% with examples of 99.8%
- Density - 0.2 - 0.5 g/ml
- Very lightweight
- Thermal conductivity = < 5 mW/mK (inert against molten metal)
Working Properties
Resources and Citations
- Institute of Materials Physics in Space: Aerogels
- Praestegaard L., G. Sorig Thomsen, K. Woer 'Before the Fire: Experiments on Fire-Protecting Cover Materials', Studies in Conservation, 68(1), 1-8, (2023) link
- Alwin, S., Sahaya Shajan, X. Aerogels: promising nanostructured materials for energy conversion and storage applications. Mater Renew Sustain Energy 9, 7 (2020).
- Skanacid A/S: www.skanacid.dk
- Supedium: The Incredible Aerogel
- Wikipedia: https://en.wikipedia.org/wiki/Aerogel
- Aerogel: What is Aeogel?