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Silica aerogels have unique mesoporous structure and properties which are widely used in many fields

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Author : TRUNNANO
Update time : 2021-01-14 09:59:04
What is silica Aerogel?

Silica Aerogel is a porous, lightweight material often used in chromatography, high-temperature insulation, optics, and various other applications. Both hydrophilic and hydrophobic silica aerogels are available in various densities and shapes such as discs, paper, fabric, blocks, cylinders, and tiles. American Elements can produce most materials in high purity and ultra-high purity (up to 99.99999%) forms and follows applicable ASTM testing standards; a range of grades are available, including Mil Spec (military grade), ACS, Reagent and Technical Grade, Food, Agricultural and Pharmaceutical Grade, Optical Grade, USP and EP/BP (European Pharmacopoeia/British Pharmacopoeia).
 
 

 
What is silica Aerogel used for?

Silica aerogels can be used in imaging devices, optics, and light guides. A material for filtration due to its high surface area and porosity, to be used for the removal of heavy metals.
 
Insulation field
Silica aerogel has a very low density. Compared with traditional insulation materials, it can achieve the same insulation effect with a lighter weight and smaller volume. Now it has been demonstrated in aerospace, military and civilian fields. Broad application prospects. For example, the British "Puma" fighter jet uses silica aerogel thermal insulation composite material as the cabin thermal insulation layer. The use of silica aerogel thermal insulation composites on weapon power devices can not only effectively prevent the spread of heat sources but also facilitate the anti-infrared reconnaissance of the weapon itself. In the field of building materials, silica aerogel is also an excellent, environmentally friendly and efficient heat-insulating and sound-proofing lightweight building material. Better transparency and good insulation also make it a promising window insulation material.
 
Optical field
The nano-porous structure of silica aerogel makes it have a long mean free path in the visible light range and has a good light transmittance. When it is used as a light-transmitting material, the reflection light loss can be neglected. The optical anti-reflection film prepared by using the optical properties of silica aerogel can be applied to the fields of high-power laser system optical components, display devices, and solar cell-protective glass.
 
Electricity field
The ultra-low dielectric constant makes silica aerogel can be widely used as high-temperature wave-transmitting materials for missiles in the electrical field.
 
Catalysis
The unique nano-porous three-dimensional network structure results in its ultra-fine particles, high porosity, high specific surface area, low density and other characteristics, which makes it have strong adsorption, and greatly improves the activity, selectivity, and life of the supported catalyst. It is superior to traditional catalysts and therefore has great application value in the field of catalysis.
 
Medical field
Silica aerogel has extremely high porosity and also has certain biocompatibility and biodegradability, so it can be used in biomedical fields such as diagnostic agents, artificial tissues, human organs, and organ components. If the drug is carried by adsorbing related solutions, it can be applied to medical behaviors such as drug-loaded delivery and controlled release systems. Moreover, the sensitive response of the silica aerogel-loaded enzyme to the reaction and existence of the organism can be used to manufacture the biosensor.
 
How is silica Aerogel made?

Silica aerogel is made by extracting the liquid from the framework of the silica gel in a way that preserves at least 50% (but typically 90-99+%) of the gel framework's original volume. This is typically done by supercritically drying the gel but can also be done a number of other ways.
 
The main process of preparing silica aerogel includes three parts:
 
Sol-gelation process: the sol is obtained through the precursor reaction of the silicon source, and then a catalyst is added to undergo hydrolysis and condensation to obtain a wet gel.
 
Aging of gel: The wet gel is allowed to stand foraging in the mother liquor to improve its mechanical strength and stability
 
Drying process: The liquid dispersion medium in the gel must dry the gas from the holes to form a silica aerogel.
 
 
How strong is silica Aerogel?

Although it's true that a typical silica aerogel could hold up to 2000 times its weight in applied force, this only holds if the force is gently and uniformly applied. Also, keep in mind that aerogels are also very light, and 2000 times the weight of an aerogel still might not be very much.
 
What is silica Aerogel made of?

Aerogels are created by removing moisture from a gel while maintaining the gel structure. The resulting material provides very effective insulation. Since their invention, aerogels have primarily been made of silica. The silica is combined with a solvent to create a gel.
 
The solid framework which makes up a silica aerogel is composed of nanoparticles of silica—the oxide of silicon—just like glass, quartz, or sand (although these forms of silica often have other components mixed in).
 
Cellulose Silica Hybrid Nanofiber Aerogels: From Sol-Gel Electrospun Nanofibers to Multifunctional Aerogels
 
Aerogels are considered ideal candidates for various applications because of their low bulk density, highly porous nature, and functional performance. However, the time-intensive nature of the complex fabrication process limits its potential application in various fields. Recently, the incorporation of a fibrous network has resulted in the production of aerogels with improved properties and functionalities. A facile approach is presented to fabricate hybrid sol-gel electrospun silica-cellulose diacetate (CDA)-based nanofibers on generating thermally and mechanically stable nanofiber aerogels. Thermal treatment results in gluing the silica-CDA network strongly together, thereby enhancing aerogel mechanical stability and hydrophobicity without compromising their highly porous nature (>98%) and low bulk density (≈10 mg cm−3).
 
X-ray photoelectron spectroscopy and in situ Fourier-transform infrared studies demonstrate the development of strong bonds between silica and the CDA network, which result in the fabrication of cross-linked structures responsible for their mechanical and thermal robustness and enhanced affinity for oils. The superhydrophobic nature and high oleophilicity of the hybrid aerogels enable them to be ideal candidates for oil spill cleaning, while their flame retardancy and low thermal conductivity can be explored in various applications requiring stability at high temperatures.
 
 
3D Printing Silica Aerogels for Small Scale Applications
 
International researchers working with the Swiss Federal Laboratories for Materials Science and Technology (EMPA), led by Shanyu Zhao, Gilberto Siqueira, Wim Malfait and Matthias Koebel, are exploring new ways to use aerogels on the microscale for additive manufacturing, detailing their study in the recently published “Additive manufacturing of silica aerogels.” Currently used in a variety of applications where thermal conductivity is required, silica aerogels may be found in optics, particle capture, physics, and more. Most commonly, though, these materials are used for thermal insulation-especially for constricted spaces that may require buffering.
 
Historically, silica aerogels have been known as difficult to manipulate because of their brittleness (often resulting in the need for additives, which may be even further limiting in terms of miniaturization), leading the researchers to develop a new, patent-pending technique for making micro-structures through direct ink writing (DIW).
 
The thermal conductivity of silica aerogel is not substantial, but the materials possess good mechanical properties. The authors report that the 3D printed aerogels can be “drilled and milled,' leaving the potential for post-processing with moldings. 3D printed samples in the form of leaves and a lotus flower were produced during the study, demonstrating not only the ability to design overhanging structures but also to print complex geometries with multiple materials. Because of the small size, these materials can also be used to insulate electronics thermally, preventing them from affecting each other while in close proximity and effectively managing conductive hot spots.
 
The researchers also created a thermos-molecular gas pump (or a Knudsen pump) from aerogel material, fortified on one side with black manganese oxide nanoparticles. Upon exposure to light, the material then warms up on the dark side and pumps gas or releases solvent vapors.
 
To demonstrate that fine aerogel structures can be produced in 3D printing, the researchers printed a lotus flower made of aerogel.
 
Such progress also lends potential for the use of aerosols in medical implants, protecting body tissue from heat over 37 degrees. Currently, the EMPA researchers seek partners interested in using the novel 3D printed aerogels for industrial applications. Check out some of their previous research studies, too, as they have developed other types of 3D printing inks made with cellulose, as well as unique molds used in the development of sensors.
 
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