Change the world of magic material – Aerogels
Aerogels are the lightest solid material in the world, also known as \”blue smoke\”, \”frozen smoke\”, \”solid smoke.\” In which a set number of excellent properties, such as ultra-low thermal conductivity, sound propagation speed, dielectric constant and refractive index, high energy absorption, specific surface area and porosity transparent, in national defense, aerospace, nuclear and civilian areas have extensive and great prospect and value, known as \”change the world of magical material.\”
The termGuinness 14
- The most solid density (<1.05kg/m³）
- the broadest range of densities (> 7 × 10²)
- the minimum pore size (~ 5nm)
- the highest aperture ratio (> 99.9%)
- the low thermal conductivity (<0.015w/m·k）
- the low speed of sound propagation (<70m/s）
- Low dielectric constant (<1.003）
- the low refractive index (<1.003）
- the low loss tangent (<10-4)
- broadest compression modulus (> 7 × 10 ^ 6) [ 123]
- [123 ] samples were first implemented [123 from comet] <10^5 N/M²)
- origin and Evolution of aerogels
maximum acoustic impedance (10 ^ 6 kg /)
the broadest range of the refractive index (116%)
the low Young\’s modulus (
(a) airgel invention in U.S.
aerogels 1931 by the United States Kistler, Stanford University Ph.D. invention. it is the reason why the inventors named aerogels, mainly gel replaced with air, i.e. no damage to the gel in the solid-state structure of the situation, the liquid component with air colloids replace it. despite this interesting material has some strange properties, but, because of the airgel manufacturing process complicated and expensive to manufacture other reasons, is not yet found in addition to the value of airgel, has not aroused attention. [123 ] (b) of military demand-driven airgel
until the 1970s, with the support of the French military propellant rocket project, Stanislaus Teichner, who find a new gel synthesis methods, significantly shortening airgel cycle, advanceAirgel applications in the aerospace, defense industry of the. After the 1980s, the United States Berkeley Lab Russo, who developed a more practical use of TEOS and carbon dioxide supercritical drying technology, just pushing and airgel commercial production possible. After entering the 1990s, setting off a boom in the world\’s first airgel, the US \”Science\” magazine Popular Science as one of the top ten airgel. Promote the use of airgel in the aerospace, defense industry and the nuclear industry, such as the United States NASA\’s \”Stardust Program\”, \”Mars lander Plan\” projects. In the 21st century, in 2002, Aspen system company under NASA (NASA) created the world\’s first commercial production of airgel insulation material of Aspen Aerogel company, began marketing application airgel in civilian areas . Subsequently, the United States through the acquisition of the German company Cabot airgel technology has begun commercial production of transparent airgel particles, to promote the application of the depth of airgel, the application on a higher level. In recent years, the United States Nanopore company, Aerojet companies, as well as the EU\’s German company BASF, Hoechst company also added to the commercial application development airgel.
(c) of airgel latecomers
of Tongji University for the first time introduced in the aerogels study the nineties the country, followed by the National Defense University, Tsinghua University, Harbin Institute of Technology, Shandong University, Nanjing University, Zhejiang University, Central South University and many other colleges and universities have entered the airgel research. Shaoxing Nano Tech 2004, the company began commercial activities involved in the airgel, followed by Guangdong Egypt Lisheng Tech involvement airgel industry, which is China\’s first involvement in the airgel commercial enterprises. At present, there are dozens of companies involved in the airgel industry, but most of all relates to the technical field of fiber composite airgel insulation material. 2013 South University Dr. Lu Bin team tackled the airgel worldwide problem – Large full transparent preparation technology and high cost problems airgel, and with the Hunan Yi-feng New Materials Technology Co. opened a high-end transparent airgel country the industrialization process. With the scale of production increase, the future is still greatly reduce the cost of space, will greatly accelerate the commercialization of high-end airgel.
airgel insulation Principle
1, a zero convection effect
Theoretical studies have shown that, when the pore size is less than 70nm airgel, due to the interaction between the air and the air molecules nano thin skeleton lost the ability to flow freely, and It is attached on opposite nanometer thin skeleton, causing a low capacity heat convection airgel.
2, a thermal barrier effect of nano-thin skeleton
thermally conductive nano thin along the main backbone of the three dimensional network structure is composed of aerogels, because the skeleton thin (~ 1nm), Further further extended heat transfer path, resulting in gas heat transfer capacity of the gel close to the minimum limit.
3, the barrier effect of multi-wall
of the heat waves in the airgel will be continuously scattering at the interface between the backbone and the nano-fine pores, because the pores of nanoporous airgel, and the high porosity, representing an increase of numerous scattering centers, limiting the radiation free path, leading to thermal radiation airgel close to the minimum limit.
airgel reason was hailed as the foreign \”to change the twenty-first century magic material,\” not only because of its many outstanding features and high performance, but also widely used need high performance in many areas: national defense, including military, aerospace, nuclear industry, security, terrorism, and traditional industrial energy saving, energy saving, environmental control, new energy development, transportation and civil engineering fields. Space industry: for the development of space exploration, rockets and other equipment, high-performance cold, shock protection, thermal protection space particle capture and landing system and so on.
: means for increasing the thermal power of naval vessels, ships and acoustic stealth environmental control, damage antiknock performance and reduce the weight vessels and the like. Air Force aircraft for enhancing smart skin, fuselage antiknock loss, engine thermal protection and landing heavy equipment airdrop protective properties and weight. To improve the performance of thermal protective tanks, armored combat vehicles and other equipment, explosion-proof, stealth and soldier protective equipment and weight loss. Improve rockets, missiles and other security level of propellant and so on. Lun Kefu for heat and nuclear radiation detecting medium nuclear installations in the nuclear industry, radiation protection and the like. High-performance insulation fire decorative wall element or integrated parts for the development of high-performance, intelligent energy-saving windows, glass walls and skylight, etc., the development of the assembly building of:
; High-performance buildings fireproof coatings, functional coatings and other high-performance buildings. Pollution control used in metallurgy, petrochemical, oil transportation, oil exploration and exploitation, power plant and other equipment and piping industry efficient energy saving, industrial wastewater and industrial waste: Industrial energy saving art . Development of new energy field : a transparent insulation material for high efficiency solar heat collecting apparatus, and efficient thermoelectric conversion device and the insulating material is high capacity negative electrode material of lithium batteries, fuel cells and other components in the fuel storage. FIELD Environmental Management : for heavy metals in the sewage, and other harmful organisms efficient adsorption treatment and high adsorption hazards emergency oil spill, efficient capture and removal of atmospheric pollutants trace ions in seawater desalination plants . Transport Field : Insulation for high transparency and non-transparent envelope of the means of transport, vibration and noise reduction, and a passive crash protection member, like car exhaust filter device efficiency. field of fine chemicals : for the efficient chemical synthesis (e.g., high efficiency catalysts, adsorbents, extraction and the like), development of high performance cosmetics (e.g., sunscreens, barrier creams, etc.), new abrasive agents in toothpaste and face cream thixotropic agents. biomedical field : for the development of cancer, diabetes and other novel drug carrier, drug sustained-release agents, hemostatic agents and the like. Pesticide art: Efficient fungicides, herbicides carrier. Electronics FIELD : The insulating material for large integrated circuits, highly sensitive sensor material, high-precision and high-definition display screen of the detector material anti-reflective coating material or the like. Household Appliances : a transparent refrigerators, microwave ovens and other high energy materials, air purifiers, water purifiers the filter efficiency of the adsorbent material and the like. outdoor sports field : a lightweight efficient winter clothes, tents and other field; financial and security field: armored, counters and other safe and efficient light bullet, proof material; Crafts art: indoor pollutants efficient absorption of environmental protection multi-functional decorations.