Aerogel is the lightest material on earth, is extremely versatile and it has the potential to change the way we live. This article is going to be a simplified introduction to the material. We’re going to cover the manufacturing process, its properties and uses.
Types of Aerogel and the Manufacturing Process:
Aerogel comes in many types, with the most common being silica aerogel. The manufacturing process begins with four main ingredients:
- Tetramethoxysilane (TMOS): Consists of four methoxy groups bonded to a silicon atom, creating a stable compound.
- Methanol: A colorless, volatile, and flammable liquid that acts as a co-solvent.
- Deionized Water: Water treated to remove all positive and negative ions.
- Ammonium Hydroxide: A basic catalyst that accelerates reactions.
To initiate the reaction between TMOS and water, ammonium hydroxide and methanol are added to create a catalyst solution. Simultaneously, methanol is mixed with TMOS to form an alkoxide solution. The two solutions are combined in a beaker with a magnetic stir bead at the bottom. This process results in the formation of silica or silicon dioxide through polymerization.
The silica thickens to create a “sol” – solid nanoparticles dispersed in liquid. This sol is then poured into molds, setting into a gel, which forms a continuous 3D network of silica in liquid water. The gel is soaked in methanol to create an “alcogel.” Subsequently, the alcogel is placed in a pressure vessel where liquid carbon dioxide is pumped in and heated to its supercritical point. This process extracts the methanol in the pores and slowly dries it off, resulting in the transformation of alcogel into aerogel.
Aerogel can be made of many different materials.
- Silica aerogel is the oldest and most common type. It is made of a silicon dioxide and is blueish in color
- RF or resorcinol-formaldehyde polymer aerogel is composed of the same material as the plastic Bakelite. They are deep red in color.
- Chromia or chromium oxide aerogel is deep blue and opaque.
- Cadmium sulphide aerogel is yellow and opaque.
- Iron oxyhydroxide aerogel is yellow
- Nickel oxide aerogel is greenish
- Iron oxide aerogel is rust red and opaque.
- Carbon aerogel is made by dehydrated RF aerogels.
Properties and Uses of Silica Aerogel:
Silica aerogel boasts several impressive properties that make it highly valuable:
- Nanotechnology: Aerogel falls under the category of nanotechnology, dealing with dimensions and tolerances of less than 100 nanometers. Its nanopores are invisible to the naked eye, opening up possibilities in nanomedicine, nanoelectronics, biomaterial energy production, and consumer products.
- Insulation: Silica aerogel’s exceptional insulating properties are demonstrated by simple tests like placing it under a heat gun with a chocolate chip. The aerogel prevents conduction and convection, making it an excellent insulator with an R-value of R20 per inch of thickness compared to R3.5 for fiberglass and R4 for EPS foam.
- Color: Aerogel’s color varies based on the wavelengths of visible light that it scatters. This phenomenon, known as Rayleigh scattering, gives aerogel its smoky blue color on dark backgrounds and yellowish hue on white backgrounds.
- Fragility: As aerogel is mainly composed of air, it is extremely fragile and prone to fragmentation and hairline cracks. While non-toxic, inhaling large amounts of silica dust can cause irritation to the throat and lungs.
- Hydrophilic and Oleophilic Nature: Silica aerogel has a natural affinity for absorbing moisture and oils. However, its hydrophilic property can be mitigated by treating it with hydrophobic compounds, making it waterproof.
Applications of Silica Aerogel:
Silica aerogel finds diverse applications due to its exceptional properties:
- It offers superior insulation in thermal wrap aerogel blankets used in historic preservation and insulating subsea pipelines.
- Its hydrophilic nature helps control relative humidity in museums and library exhibitions.
- NASA utilizes aerogel to capture comet dust and protect electronics on Mars rovers from moisture absorption.
- It can be employed for cleaning up oil spills and has a significant oil absorption capacity.
- Cryogel blankets provide insulation in cold temperature environments, while Pyrogel blankets are suitable for hot environments.
- Aerogel is even making its way into the clothing market, enhancing warmth-to-weight ratios in jackets, gloves, and insoles.
In conclusion, aerogel is a fascinating material with immense potential in various industries, and its continuous research and development will likely yield even more exciting applications in the future. For further insights into carbon aerogel, graphene, and the specific use of aerogel in construction, stay tuned for our upcoming videos. Explore the wonders of aerogel and its promising contribution to advancing technology and our way of life.
https://www.youtube.com/watch?v=AeJ9q45PfD0 VERITASIUM
https://www.youtube.com/watch?v=GcdB5bFwio4 VERITASIUM
https://www.youtube.com/watch?v=AlohrrK6u4k HOW ITS MADE
https://www.youtube.com/watch?v=Y0HfmYBlF8g NILERED
https://www.youtube.com/watch?v=GEr3NxsPTOA Flachzange1337
https://www.youtube.com/watch?v=7AdCddOzPCo&t=201s Aspen aerogel
https://www.youtube.com/watch?v=7AdCddOzPCo&t=177s Aspen aerogel
