Look at this picture, what do you think it is?
Blue square solid?
A frozen cigarette?
To be precise, this is not only a solid, but also a type of gel. It is the lightest solid in the world – aerogel.
Before talking about aerogels, let’s briefly understand what a gel is.
For a certain concentration of polymer solution or sol, under appropriate conditions, the viscosity gradually increases, and finally loses fluidity, and the entire system becomes uniform in appearance. And maintain a certain shape of elastic semi-solid, this elastic semi-solid is called gel.
When the gel removes most of the solvent, the liquid content in the gel is much less than the solid content, or the spatial network structure of the gel is filled with The medium is gas and the surface is solid, which is called aerogel.
There are many types of aerogels, including silicon series, carbon series, sulfur series, metal oxide series, metal series and so on.
Currently, the lightest aerogel is a “full carbon aerogel” with a density of only 0.16mg/cm3 (excluding air density). It is 1/6 of the density of air.
Because the particles inside are very small (nanometer scale), visible light is less scattered (Rayleigh scattering) when passing through it, just like sunlight passing through air.
Since more than 80% of aerogel is air, it has a very good heat insulation effect. One inch of aerogel is equivalent to 20 to 30 ordinary pieces of airgel. Thermal insulation function of glass.
Even if the aerogel is placed between the rose and the flame, the rose will not be damaged at all.
Aerogels are also used in a variety of aerospace exploration applications, including the Russian Mir space station and the American Mars Pathfinder probe. to this material.
Aerogel was originally named by S. Kistler. Because he successfully prepared silica aerogel using supercritical drying method, airgel was Gel is defined as a material obtained by supercritical drying of wet gel, which is called aerogel.
The preparation of aerogels usually consists of a sol-gel process and supercritical drying.
During the sol-gel process, nanoclusters with different structures are formed in the solution by controlling the hydrolysis and polycondensation reaction conditions of the solution.
The clusters adhere to each other to form a gel.
The solid skeleton of the gel is surrounded by the liquid reagents remaining after the chemical reaction.
Although aerogel has been around for a long time, it really made aerogel “out of the circle” and reached the point of fame.
In the past two years, clothes made of aerogel have appeared on the market!
However, one thing to note here is that because aerogel is a solid, if it is to be used in clothing, it can only exist in the form of powder particles.
In other words, aerogel needs a carrier. Add the airgel powder to the coating liquid and finish it on the fabric through a process.
The current main technology is to put aerogel in the fiber without changing the physical form of the material.
There is no need for myths about the application of aerogel in clothing. After all, there is still a difference between the powerful performance of the material itself and its actual application.
After all, user experience and actual effects still need to be further considered and weighed.
Of course, we also believe that with the advancement of technology, there may be new breakthroughs in the next generation aerogel process. Let us look forward to it together!
