Nanotechnology in the Paints and Coatings Industry

What is Nanotechnology?

Nanotechnology is one of those many new technology buzzwords that are accepted in daily discourse but not very well understood as the magnitude is outside the normal scope of human dimensions. Nano means 1 billionth of a metre. For illustration, a human hair is 50,000 to 100,000 nanometres thick. This scale is more common among scientists, for instance, in memory chips, DNA research, and so on.

Nanotechnology in paint

Nanotechnology in paint consists of including nano-size particles with certain properties. Many different nanoparticles go into paint to serve a specific purpose such as self-repairing, heat resistance, reflection and pollutant capturing. While this represents progress in the quality of paint, one must be mindful of the limitations. Self-repairing happens when the nanoparticles, through erosion or damage, get exposed to sunlight. This triggers a reaction in the nanoparticles to release a bonding-type fluid that seals the crack. Realistically, given the size of nanoparticles, only small cracks in a painted wall can be repaired.

From theory to practice: Nanotechnology advancement

As scientific progress continues to be made, for theories to achieve commercial application is often a lengthy process. An example is how science has realised nuclear fusion, the holy grail of clean energy, but it is still many years away for a commercial power station based on fusion to be a reality,

Plasmonic paint which reflects the entire infrared spectrum, thereby absorbing far less heat, is an example of how nanotechnology can be used in the advancement of paint technology. University of Central Florida researcher Debashis Chanda commented that this is a glimpse of what will be possible in the future. He stated that one would (in theory) only need 1.4kg of plasmonic paint to cover a Boeing 747 of over 500m², which would otherwise need about 450kg of normal paint. Plasmonic paint only requires a thickness of 150 nanometres, that is over 300 times thinner than a human hair. One can understand that today applying such thin coat still has some hurdles to cross.

Progress of Nanotechnology in paints and coatings

As reported in the WOW report on the paint industry in South Africa, nanotechnologies have been extensively incorporated into functional coatings. Some examples of functional coatings used for green buildings include hydrophobic coatings (used on concrete to avoid concrete swelling, cracking, scaling, and chipping), photocatalytic coatings (which help to break down air pollutants such as nitrogen oxides and greenhouse gases), and coatings to reduce surface solar radiation. Paint that gets its colour from aluminium nanoparticles instead of pigment is also lightweight and reflective.

Nanotechnology in paint improves quality and endurance, offers many ecological and other benefits, and enables coatings to meet specific applications such as stretching and flexing in high-rise buildings or providing self-cleaning and antireflective coatings on glass facades.

In South Africa, nanotechnologies have already made significant inroads into the paint industry, with functional coatings contributing to green building practices. These coatings encompass hydrophobic solutions to protect concrete, photocatalytic coatings that break down pollutants, and lightweight, reflective paint that derives colour from aluminium nanoparticles, enhancing paint quality and  aligned with ecological and sustainability goals.