Everything around us is comprised of matter, defined as a physical substance which occupies space and possesses rest mass, this means the substance in general is not moving. Matter is made up of four fundamental states; Solid, Liquid, Gas and Plasma.
Drawing your attention to the solid state of matter, a solid in terms of particles is a substance where the particles are tightly packed together. A solid is described by its structural rigidity and does not change shape or volume.
Science and ingenuity have enabled us to discover, develop and invent new objects and materials in the past. In 1931 a chemical engineer by the name Samuel Kistler discovered a synthetic porous ultralight material extracted from a gel called aerogel also known as ‘solid-air’ or ‘frozen smoke’.The material is extremely lightweight with a very low density, this is due to the liquid component of the gel being replaced with a gas, approximately 98% of the aerogel is made up of air. In the early stage, the first aerogel was silica based. It was deemed the lightest human-made solid on the planet until a lighter carbon-based version of the aerogel replaced it.
As science and technology advanced, stepping into the 21st century, a group of scientists led by Gao Chao at Zhejiang University stumbled upon a mutation of the aerogel now known as aerographene or graphene aerogel. As of 2013, aerographene is known as the least dense solid created by man. In other words, aerographene is the lightest solid in the world. It is said to be approximately 7.5 times lighter than air.The material is made up of a mix of aerogel and graphene. Aerographene contains carbon nanotube supports in the interior structure which is surrounded by a graphene exterior. The material is created using a new method called lyophilization, diving into the technicality, the process involves freeze-drying hybrid solutions of carbon nanotubes and graphene, this results in the materials carbon sponge outlook. Due to the nature of the sponge being able to take the shape of any container, the material can be manufactured in sizes up to thousands of cubic centimetres and can take up a variety of forms.
The initial applications for aerographene makes use of its spongy nature. The material can rapidly absorb up to approximately nine times the amount of its weight in petroleum. Due to this mind-blowing feature, aerographene will be used to clean up large scale oil spills. After further testing, it was clear that aerographene could be used to manufacture other ultralight weight composites.
The properties in the aerogel and graphene also make it a high thermal conductivity and therefore gives the material qualities such as being a good insulator. Aerographene is also a phase change material used for storing energy. Due to the sponge replication, the material can absorb and release sufficiently large amounts of energy during phase transition to provide useful heating and cooling.
Aerogels have also made its unique use and abilities in space travel. A team at NASA is currently working on a project called the Hypersonic Inflatable Aerodynamic Decelerator (HIAD). Its purpose is to shield and protect any payload as well as the spacecraft when entering an atmosphere. It will be used to slow the spacecraft down and enable a safe descend and landing. The HIAD is covered by a flexible thermal protection system, using aerogels as an insulator to protect the payload and prevent overheating.