What is aerogel?
Aerogel is created by combining a polymer with a solvent to form a gel, and then removing the liquid from the gel and replacing it with gas (usually air). The high air content (99.98% air by volume) makes it one of the world's lightest solid material. Aerogels can be made from a variety of chemical compounds, and are a diverse class of materials with unique properties. They are known as excellent insulators, and usually have low density and low thermal conductivity.
Aerogels can be used in various applications, and although they have been around since the 1930s, their development is still progressing (for example, NASA's Glenn Research Center in Cleveland has invented several groundbreaking methods of creating new types of aerogels).
Common applications include enhancing the thermal performance of energy-saving materials and sustainable products for buildings, acting as a high performance additive to coatings, prevention of corrosion under insulation, uses in imaging devices, optics, and light guides, thermal breaks and condensation control, architectural lighting panels, outdoor and sports gear and clothing, and more.
Graphene aerogel, also known as aerographene, is considered to be the least dense solid in existence (graphene aerogels are light enough to be balanced on small plants!).
Graphene aerogels are quite elastic and can easily retain their original form after some compression. In addition, the low density of graphene aerogels makes them very absorbent (to the point where it can even absorb more than 850 times its own weight). This means that it could be useful for environmental clean-ups like oil spills, and the aerogels only need to be picked up later after absorbing the spilled material. Graphene aerogel may also have some applications in both the storage and the transfer of energy by enabling the creation of lighter, higher-energy-density batteries - and vigorous research is being done on the matter.
Graphene aerogel are somewhat similar to graphene foams. Graphene foams are usually made by CVD growth on a metal structure (which is later removed), and are so more conductive than graphene aerogels.
Graphene aerogels are already being sold commercially, for about about $300 per gram.
The latest Graphene Aerogel news:
Researchers at Zhejiang University in China have designed a new type of aerogels, made of graphene and carbon nanotubes, that can be reversibly stretched to more than three times their original length, displaying elasticity similar to that of a rubber band. This stretchability, in addition to aerogels' existing properties like ultralow density, light weight, high porosity, and high conductivity, may lead to exciting new applications.
The scientists designed carbon aerogels consisting of both graphene and multi-walled carbon nanotubes assembled into four orders of hierarchical structures ranging from the nanometer to centimeter scale. To fabricate the material into aerogels, the researchers created an ink composed of graphene oxide and nanotubes, and then formed the aerogels via inkjet printing.
The PolyGraph project, a 4-year development project with aims to develop new production techniques to deliver industrial scale quantities of graphene-reinforced thermosetting polymers, has published its results.
The POLYGRAPH (Up-Scaled Production of Graphene Reinforced Thermosetting Polymers for Composite, Coating and Adhesive Applications) project brought together 14 partners, including SMEs, companies, universities and a research center, and has reportedly led to the identification of the most suitable materials and production techniques for graphene-based coatings, adhesives and composites. Once the graphene market reaches maturity and material prices drop , these new products could appeal to a vast range of industries.
A research team from the Paul Scherrer Institute in Switzerland and Sapienza University in Rome developed a new loud speaker that is driven by a light signal - and without electricity. The idea is to use modulated light that shines on a 3D graphene sponge. The audio is achieved via a highly-efficient photo-mechanism.
The researchers say that unlike conventional loudspeakers, this high-fidelity photo-speaker does not rely on vibrations to produce the sound - and it does not need any type of electrical connection or complicated system for sound generation. Using an optical pulse train, this loudspeaker allows a completely digital operation for frequencies from acoustic to ultrasound.
Imagine Intelligent Materials and Swinburne University have announced a collaborative six-month project aiming to develop graphene-reinforced smart composites. The composite will be able to report on the condition of large structures, and will have major commercial potential in the transport sector, including automotive and aerospace.
The project is supported by a $20,000 Seed grant from the university under a program, targeting “interdisciplinary projects that are aligned with the Swinburne research institutes’ external partnership and collaboration objectives”. It will combine expertise from experts in sensors, electronics engineering and aerospace manufacturing at the university.
A collaboration work by Purdue, the Chinese Lanzhou University and Harbin Institute of Technology, and the U.S. Air Force Research Laboratory has yielded a lightweight, flame-resistant and super-elastic composite shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.
The composite material is made of interconnected cells of graphene sandwiched between ceramic layers. The graphene scaffold, referred to as an aerogel, is chemically bonded with ceramic layers using a process called atomic layer deposition. The team explained that graphene would ordinarily degrade when exposed to high temperature, but the ceramic imparts high heat tolerance and flame-resistance, properties that might be useful as a heat shield for aircraft. The light weight, high-strength and shock-absorbing properties could make the composite a good substrate material for flexible electronic devices. Because it has high electrical conductivity and yet is an excellent thermal insulator, it might be used as a flame-retardant, thermally insulating coating, as well as sensors and devices that convert heat into electricity, said associate professor in the School of Industrial Engineering at Purdue University.