Scientists Develop Nanoscale Material to Control Fire

The researchers developed a method called inverse thermal degradation (ITD), which uses a nanoscale protective layer to control the flame's interaction with the material. This allows for proper processing of the properties of finished products, as demonstrated by the creation of microscopic carbon tubes from cellulose fibers.

Scientists Develop New Nanoscale Material That Can Control Fire

High-temperature flames are essential for producing numerous materials. But managing fire and how it interacts with the target material may be difficult. Researchers have now created a technique that employs a molecularly thin barrier to regulate how flame interacts with the material, put out fires, and enable users to fix damaged areas of final items.
Fire is a necessary engineering tool because blast furnaces are just a very hot fire, says Martin Thuo, professor of materials science and engineering at North Carolina State University and author of the published study. But once under fire, you usually have little influence over how it behaves.

Inverse Thermal Degradation (ITD)

“Our method, which we refer to as "inverse thermal degradation" (ITD), makes use of a thin nanoscale coating on the target material. The thin coating adjusts in reaction to the fire's heat and controls how much oxygen can reach the substance. That suggests we may influence the rate at which the material warms up, which in turn impacts the chemical reactions taken on inside the material. We have control over where and how the fire changes the material.”

How Inverse Thermal Degradation (ITD) works

Here’s how ITD works. You begin with the substance you want to use, in this case, cellulose fiber. Then, a nanometer-thick covering of molecules is applied to that fiber. A strong flame is then held over the coated fibers. The molecules' exterior surfaces quickly ignite, elevating the temperature in the nearby area. However, the molecular coating's inner surface undergoes chemical modification, resulting in an even thinner glass layer encasing the cellulose fibers. By limiting the amount of oxygen that may reach the fibers, this glass keeps the cellulose from burning. The strands smolder instead, slowly consuming themselves from the inside out.

“Without the protective layer of ITD, applying flame to cellulose fibers will only produce ash. said Thuo. Carbon tubes make up the ITD's outermost layer of defense. “The amount of oxygen that reaches the target substance may be adjusted by engineering the protective layer. Additionally, we may modify the target material to add desired properties.”

The researchers conducted a proof-of-concept demonstration with cellulose fibers to produce a tiny carbon fiber.

The thickness of the walls of the carbon tubes may be altered by the researchers by adjusting the size of the cellulose fibers. Adding more salt to the fibers (which further controls the burning rate), and varying the amount of oxygen that passes through the protective layer.

“Future research will include many of the applications we are currently considering," said Thuo. “We are also ready to work with the private sector to explore various practical applications, such as the development of carbon steel engines for oil-water separation useful for industry, printing, and environmental purification.”

Reference 

"Spatially Oriented Pyrolysis via Thermally Deformable Surface Additives" Sau: Chuanshen Du, Paul Gregory, Dhanush U. Jamadgni, Alana M. Pauls, Julia J. Chang, Rick W. Dorn, Andrew Martin, E.Johan Foster, Aaron J. Rossini, and Martin Thuo, 19 July 2023. Angewandte Chemie.

DOI: 10.1002/anie.202308822