#Aerogelove – love is in the gel…

For me the feeling towards aerogels started 2 years ago. I was walking in the library at Stanford University when I saw a book Stuff Matters of Mark Miodownik about “exploring the marvellous materials that shape our man-made world”. In the book it was a photo of him, sitting at the chair on a concrete roof, drinking coffee from the porcelain teacup, eating chocolate, writing on a piece of paper. Every chapter was dedicated to a certain material from the photo, the history of its discovery, applications and future challenges. Among them appears a “marvellous” material – aerogel, the best known thermal insulator, composed in 1% of silica and in 99% of empty space.

For Mark Miodownik the story started 20 years ago when he was working at the nuclear laboratory in New Mexico for US government. Once staying in the lab, he observed a technician, who was taking an opalescent, lightly blueish, strange sample out of a microscope, which looked like a hologram. At first, he thought it is so weird that it had to reach our civilization by an alien spacecraft. He has not been given much more information about this “ghost material”, used for a secret project. Finally, his curiosity has been satisfied in January 2004. when NASA’s Stardust project captured particles from the tail of the comet Wild2. The dust particles have a speed comparable to the bullet – 6/km per hour, so how to catch something that fast and do not destroy it internal structure? Dr Steven Jones of NASA’s Jet Propulsion Laboratory came up with an ingenious solution – creating aerogel with gradient density for optimum energy dissipation. The scientists at NASA have decided to take the lightest solid material, with a density comparable to air. They had to wait for six years for the capsule to come back to check if that was a good choice. It was, as the particles where gently embedded into the aerogel structure, bringing the information from the time of formation of the Solar System.

This light as the sky material was invented 1930s Samuel Kistler, a chemical engineer at Stanford University. Working in the lab he made a bet with his friend Charles Learned „to see if they could replace the liquid inside of a jelly jar without causing any shrinkage”, which was a difficult task due to the capillary force. A complete success of this experiment resulted in publishing a paper on coherent expanded aerogels and jellies in Nature in 1932. For decades the way of production was too expensive to make them commercially applicable, but nowadays the obstacles can be daily overcome with the current technology, and due to the set of astonishing, adsorptive, acoustic, and thermal insulating properties, aerogels are getting back to bring more and more attention.

This year we invited two extraordinary experts to join our Scientific Design Course, who are daily working with aerogels: Dr Ioannis Michaloudis, an artist and professor of Visual Arts from Charles Darwin University in Australia and Dr Mihail Petkov from Jet Propulsion Laboratory at NASA.

Having Mihail Petkov as a mentor, who works closely with Steven Jones and has taken a part in several Mars missions, like Spirit and Opportunity in 2003, Curiosity in 2012, InSight 2018 has been actually a great Opportunity to feel the Spirit, obtain the scientific Insight on and fulfil the Curiosity on insulating properties of silica aerogels. First, we asked him about the definition of aerogels.

Mihail Petkov: Aerogels are a class of sol-gel materials, which are usually prepared in two steps – making a sol and gelling the sol. The sol contains functionalized nanoparticles formed from a precursor of choice (organic, inorganic). Then a catalyst is added and that forms a solid network, with the solvent trapped inside, called wet gel. The wet gel can be dried in three different ways.

1. supercritically, which avoids crossing the vapor-liquid phase transition line in the pressure-temperature phase diagram in order to avoid pore collapse under capillary pressure. These are called aerogels;
2. cryogenic cooling and pressure reduction to cross the solid-vapor phase transition boundary (to avoid liquid in the pores again); these are called cryogels;
3. ambient drying, which results in liquid formation in the pores that leads to pore collapse, but it’s the cheapest way and all the industry is targeting that. These are called xerogels; 

The aerogels (xerogels or cryogels) are usually characterized by nitrogen adsorption (BET method, from Brunauer-Emmett-Teller) and Scanning Electron Microscopy to look for pore sizes. This is just to show how good the material is, but pore size and surface area are two parameters that go with aerogels like a person’s name.

While the scientists are looking for a truth, the artists will look more into the beauty. Those can be two complementary ways of describing and understanding the same reality. “Truth” and “beauty” were the original names for the heaviest complementary pair of quarks, identified with “t” and “b”, unfortunately, those names never caught up.

Our mentor Ioannis Michaloudis in the article published in 2014 in Acta Astronautica: “Etherospermia: Conceptual art, science and allegory in the sky-seeding project”, points out that although science is able to provide experiments it does not give a full experience, especially in case of aerogel – a “free-dimensional” material. On the opposite of rigid scientific methodology, which is able to measure objects in a geometrical space, art is giving a way to feel them, by “visual senso-motoric perception”, in so-called representative space – a term introduced by French mathematician Henri Poincare. Here, the beauty comes from the inner structure and the light scattering effects, which decide about the colors of aerogel: a light blue, appearing when aerogel is on a black background and a yellow-orange if the light passes through it in transmission mode. This the same reason, why we are able to enjoy the colors of the sky instead of looking into the dark space. So maybe inspired by the beauty we open the mind, starting to ask questions, and then looking for the answer we improve the understanding and, in the end, appreciate it even more. It is very close to another quote of Henri Poincare: “If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living”. Thus, we should not treat scientific and artistic approach as two alternative descriptions, but rather two complementary visions of the same reality.

The natural beauty and an internal spirit of aerogel become clear when you have a chance to get familiar with aer()sculptures: Icare, I care, (L)imited Sky, (M)other Earth(s) are artworks of Ioannis Michaloudis). It is not only an invention of presenting an idea in a piece of sculpture but an idea of an incentive inspiration, including a poetry game with the meaning of the words. He also told us that a role of art is to ask questions, and a role of science is to look for the answers. The question he asked himself was a real challenge: Can you touch the sky? Put it in between your fingers? Feel something which cannot be easily measured, only in less than 1% being material. With a passion of the sky, he went with the project further, to make the portable sunset and succeeded in creating the moving cloud inside of the solid part of the sky. His ingenious Save our Sky SOS signal marks the necessity of protection of the sky and the atmosphere, essential for human existence. Especially at that very moment, when we struggle so much with the air pollution and space debris. A remarkable message, that it is not going to be forgotten for potentially billions of years, as two of his aerogel artworks were selected by t/he MoonArk project, to be launched to the moon on Falcon9 rocket in 2019.

Aerogelove, read in Polish, means made of aerogels. What kind of things can be made of aerogel – the material of the future? This is the task of our students to “Do something with 99% of nothing” and come with an idea of creative applications in various types of fields: medicine, transport, architecture, space technology, electronics and energy. A journey of a thousand miles begins with a single step. How to make the first step? Here our mentor also has an advice: having an idea, you should start visualizing and try to make the sketch, deciding about the shape, material and do not forget about the color.

The future is shaped by our imagination and implementing ideas, the sky has no limits, especially for the material light as the sky.

Author: Aleksandra Szkudlarek

PS. This year I have met quickly Mark Miodownik at Copernicus festival in Krakow, we chatted for a while and I told him about this project of comprehensive education. Giving him a book, to sign his left a message Stick to the dream and Keep it material!

I would like to acknowledge Dr Mihail Petkov and Dr Ioannis Michaloudis, who gave suggestions and many inspirations for this article and greatly contributed to our project and to Aleksandra Koper for some inspirational thoughts.