EL PERIÓDICO and the Barcelona Materials Science Institute (ICMAB, CSIC) will publish a series of videos and articles every Wednesday until September 7 within the framework of the popular science project ‘YouMaker: this is how science is done’. This is content in which various experts will explain in a didactic way the processes for preparing materials used in the fields of energy, electronics and medicine, such as batteries or solar cells, from their laboratories and with the participation of professional science communicators.
Have something in your hands, but without noticing that you have it. This is what happens when you hold a piece of airgel in your hands. A solid material, but very porous, almost as dense as air. The lightest solid material on the planet. It has such a porous structure, like a sponge, that it weighs nothing, and is almost transparent. The walls of the material are very thin and it is very fragile, it breaks right away. Why can such a material serve? And how is it made?
An ICMAB research group, led by researcher Elies Molins, is working on this. They are experts in manufacturing aerogels of different types. The most common are those made of silica or, what is the same, silicon oxide, the material from which glass is made, and sand. They are used mainly by the Elies group to obtain hydrogen from mixtures of alcohol and water. Hydrogen, the energy of the future, some say. And what does airgel have to do with all this? Well, airgel, being so porous, also has a very large surface area. In just one gram of airgel there is 600 square meters of surface, like a football field! Yes, I know it’s hard to imagine, but it is so. And it is on this large surface where the chemical reactions that transform alcohol into hydrogen take place, also thanks to some nanoparticles of gold, titanium oxide or other elements, which are introduced into this porous material.
supercritical conditions
And how is it made? I will only tell you that supercritical conditions are needed, which with that name already sounds quite good. Supercritical conditions are conditions of pressure and temperature where the system is neither gas nor liquid, but rather both and nothing at the same time. Under these conditions, the liquid inside the pores turns into a gas without boiling or the system collapsing, achieving an airgel with a very good porous structure.
Related news
If you want to know more about aerogels, and want to see how they are made, watch the video “How is an airgel made?” with the science communicator Andrea Stephany and the researcher from the ICMAB Crystallography group Elies Molins, who have done within the framework of the YouMaker project: this is how science is done. You will be surprised to see what other applications these particular materials can have.
“YouMaker” is a project of the Barcelona Institute of Materials Science (ICMAB, CSIC) in collaboration with the Spanish Foundation for Science and Technology (FECYT) of the Ministry of Science and Innovation.