Nanoscale Thin Film Controls How Flame Interacts With a Material, Provides New Way of Regulating Fire

Fire can be both dangerous and useful. When properly handled, it can supply us with the energy and heat that we need to perform our daily activities. Otherwise, it can cause damage to properties and harm people. Traditionally, fire is controlled using water, foam, and other chemicals to extinguish flames. Recently, researchers have discovered a new approach to controlling fire using nanoscale materials.

Nanoscale Thin Film Controls the Way Flame Interacts With a Material, Provides New Way of Regulating Fire

(Photo: Pexels/ Pamoni Photograph)

The Chemistry of Combustion

Fire is produced with the evolution of heat and light, resulting to a reaction called combustion. Three main ingredients are needed for fire: oxygen, heat, and fuel. When enough heat is applied to a source of fuel and in the presence of oxygen in the air, fire is formed.

When the atoms in the fuel heat up, they start to vibrate until they are released from the bonds that hold them together, releasing them as volatile gases. These gases chemically react with oxygen in the air and form so much heat that can keep driving the reaction. This way, the response becomes self-sustaining if there is enough fuel and oxygen. Flames are produced at a certain point in the combustion reaction called the ignition point. They result from releasing some of the heat energy generated as light.

These components have led to the development of the "fire triangle." When one of these components is removed, fire will not be produced, or an existing one will be extinguished.

New Fire Management Approach

As nanotechnology is increasingly used in almost every aspect of the economy and society, it has also advanced its application in fire protection. Nanostructures are already found in elements used as direct protection against fire.

Researchers from North Carolina State University developed a strategy to control the flame's heat's interaction with a combustible object. This was done by suppressing the fire and allowing the users to control the characteristics of the processed material.

The technique is called inverse thermal degradation (ITD), which uses a nanoscale thin film over a targeted material. In response to the heat of the fire, the thin film changes and regulates the amount of oxygen that can reach the material. As the rate at which the material heats up is controlled, it influences the chemical reaction within the material. In short, the user can fine-tune how and when the fire changes the material.

Corresponding author Martin Thuo described how ITD works, starting with the target material, such as a cellulose fiber. A nanometer-thick layer of molecules coats the fiber, which is then exposed to an intense flame. Since the outer surface of the molecules easily combusts, the temperature in the immediate vicinity is raised.

However, the inner surface of the molecular coating changes chemically, which creates a thinner layer of glass around the cellulose fibers. This glass layer limits the amount of oxygen reaching the fiber and prevents the cellulose from bursting into flames. As a result, the fibers slowly burn from the inside out.

This new material can have many applications, from firefighting technology to construction materials and even clothing. It can be used in space exploration where the traditional method to control fire is not practical.