“The so-called aerogel is a thousand times lighter than conventional gold alloys. It is lighter than water and almost as light as air,” said lead researcher Raffaele Mezzenga. To make the foam, Mazzenga and his team first heated milk proteins to create tiny fibers, called amyloid fibrils. These fibrils were then added to a gold salt solution, which produced a “three-dimensional, lattice-like structure.” As this happened, the gold crystallized and embedded itself into these fibrils, and the consequential gel-like substance was dried to give way to a foam.
This aerogel doesn’t have to be the lovely golden hue that is expected of the 20 carat metal, but it can also be dyed into different colors. “The optical properties of gold depend strongly on the size and shape of the gold particles,” the study’s lead author Gustav Nyström, said in a statement. “Therefore we can even change the colour of the material. When we change the reaction conditions in order that the gold doesn’t crystallize into microparticles but rather smaller nanoparticles, it results in a dark-red gold.”
While the incredible aesthetics of the foam are an accomplishment in and of themselves, the team believes that the new substance has considerable implications in the chemistry field, especially in chemical catalysis. And of course, jewelry will never be the same again.
So while you may not be able to froth gold at home to top of your morning cup of Joe, you may find gold foam in other applications some day soon.
