'Explosive seepage' process brings advanced conductive coatings

According to a new study published in the journal Nature Communications, researchers at the University of Sussex in the UK have developed a highly conductive polymer nanocomposite using an "explosive percolation" process that resembles the network of a virus spread. The discovery was an accident and a scientific first for the researchers.

An important component in the development of liquid technology is the percolation process, which is the statistical connectivity in a system, such as when water flows through soil or coffee grounds. "Explosive percolation" is a mathematical process that can also be applied to population growth, financial systems and computer networks, but has never been seen in material systems, which is what the researchers wanted to see.

In experiments, the researchers added polymer latex spheres to graphene oxide. By drying this solution, like drying paint, the graphene oxide is trapped between the spheres, and as more graphene is added, these graphene flakes eventually form a "percolation" network within the latex film.

However, since graphene oxide does not conduct electricity, the researchers applied some mild heating (150°C, similar to the temperature of a heat gun used to dry paint) to eliminate chemical defects. At this point, the films were not only conductive as expected, but also more conductive than films made entirely of graphene. They witnessed an exponential increase in electrical conductivity.

This emerging material behavior leads to a new solution for highly conductive coatings, as graphene oxide is a nanomaterial that is cheap and easy to produce at scale. Conductive coatings and inks have a range of applications in new printing technologies, such as imparting properties to coatings such as antistatic or creating coatings that block electromagnetic interference (EMI), and are also critical in the development of wearable health monitors.

The researchers say the development of percolation networks in this experiment is similar to the emergence of highly transmissible virus variants, allowing scientists to use epidemic models to develop exciting new materials.

The researchers also pointed out that due to the cheap and scalable properties of graphene oxide, this achievement will lead to affordable highly conductive polymer composites, thereby greatly improving the sustainability of electric vehicle materials including batteries. , and the possibility of adding conductive coatings to materials such as ceramics.

Percolation is one of the basic problems in mathematics, statistical physics and network science. It is also often used to analyze virus propagation, information dissemination and social relations. Explosive seepage is a vivid description of complex networks. When something reaches a threshold, it will cause explosive or even uncontrollable changes. The researchers creatively applied this theory to the generation of new materials, allowing graphene flakes to form a "percolation" network within the latex film. The conductive system composed of graphene films grew exponentially. Researchers believe that similar methods can allow scientists to use epidemic models to develop new materials, which once again highlights the role of disciplinary integration in promoting innovation.