Using the Super-Growth single-wall carbon nanotubes (SGCNTs), the researchers have developed an aqueous paint that can be formed into a thin film with a strong shielding effect against electromagnetic waves.

Film formed on a polyimide sheet using the SGCNT-based aqueous paint

The SGCNT-based aqueous paint (left) and applying shear rate dependence of its viscosity (right)

A 10µm thick film formed using the developed SGCNT-based paint is characterized by a strong electromagnetic wave shielding effect: 99.9% shielding on GHz region. In addition, it can be applied on a wide variety of base materials, since no organic solvents are used. Further, the formed film is flexible, and therefore it is resistant to bending and can follow deformation of the base material. It is also resistant to temperatures as high as approximately 180 °C.

With the advancement of communication devices, the demand for technology to shield unnecessary electromagnetic waves to prevent malfunctions has increased. A protection method that uses a metallic casing has been conventionally employed as one technique for shielding against electromagnetic waves. Recently, methods such as one that applies an electromagnetic wave shielding paint on a part with a complex shape made of a material such as resin, have been attracting attention with the goal of reducing device weight.

However, existing electromagnetic wave shielding paints are based on metal particles and use organic solvents, so the types of base materials that can be applied with such paints are limited. Use of paints is also limited due to the deterioration of formed thin films under harsh environments, such as a high-temperature, high-humidity environment. In addition, there are problems such as a low shielding effect.

The researchers will form electromagnetic wave shielding films using the developed SGCNT-based aqueous paint on base materials provided by companies, and provide them as samples.