Aerogel is a synthetic material derived from a gel, a mixture where liquid particles are dispersed throughout a solid medium. Aerogel differs from other gels – gelatin, for example – in that its liquid components have been replaced with gas. This gives aerogel its extremely low density – so low that a piece the size of a family car is no heavier than a kilogram. It is so light that its descriptive names include “solid air” and “frozen smoke.”
It starts out as a wet silica gel mixture comparable to jelly, which is then dried out to produce one of the most porous materials known to mankind. Its water content is carefully removed to prevent damage to its delicate silica structure – a long, meticulous process that ends up raising the material's price tag. As few American homeowners can afford it, most of its applications involve highly specialized tasks, such as collecting stardust in space. (Related: Researchers have recycled clothing waste into an “aerogel” supermaterial that can help stop wound bleeding.)
In their study, published in the journal Advanced Materials, the researchers discussed how, instead of using high pressure and temperature, they used sodium bicarbonate (more commonly known as baking soda) to “blow” out water molecules while keeping carbon dioxide trapped in the material's pores. This was inspired by observations of how dragonflies dry out their wings after emerging as adults.
"A dragonfly's wings are an ultralight aerogel -- making up less than 2% of the insect's total body weight -- and yet they are so strong they can carry the insect thousands of miles across oceans and between continents," said Dr. Lidija Šiller, a nanoscale scientist at Newcastle University and one of the authors of the research.
Dr. Šiller explained that most of a dragonfly's life cycle is spent living underwater as a larva. After 30 days to several years – depending on species – the animal transforms into an adult capable of flight. When it first emerges from its larval skin, its wings have jelly-like properties.
Dragonflies dry out their wings by producing bicarbonate molecules. These produce carbon dioxide which regulates their body's pressure and removes the water from their wings, making them sturdy and stable enough to be used for flight.
She said that it was only a matter of replicating the process in a laboratory and blowing out the water at ambient temperature.
With its unique characteristics, aerogel could possibly be the best insulation material for homes and other buildings.
The researchers said that when increased in scale, their technique can lower the cost of aerogel from about $100 per kilogram to just $4 per kilogram, making it more accessible to the public.
"The potential of this discovery in terms of reducing energy use and therefore our energy bills is really exciting,” Dr. Šiller said.
The research was funded by the Engineering and Physical Sciences Research Council (EPSRC).
Catch more stories about aerogels and other technologies of the future at FutureSciencenews.com.