Domestic researchers have developed a novel material that can block 100% of light by freely stretching a transparent vinyl-like film. With its ability to easily control light transmission and its high elasticity, it is expected to be applicable in various fields such as wearable devices, flexible displays, and smart windows.

The Electronics and Telecommunications Research Institute (ETRI) announced on the 11th that it has developed a transparent polymer film capable of freely controlling light transmittance.

This technology was featured as a cover article in a journal published by the Royal Society of Chemistry (RSC) at the end of last month.

The film developed by ETRI researchers is a film that can expand and contract without adding light intensity control materials or particles, and can block light transmittance up to 100%.

The research team created it using a photocuring method that hardens a polymer solution with light. The polymer and solvent contained in the polymer solution are chemically bonded through light.

The research team identified the relationship between light-reactive polymer materials and solvents, and found the optimal content ratio to naturally disperse the polymers into nanoparticle sizes.

The change in transparency occurring in the film is due to this ratio.

With this, we succeeded in developing a polymer solution capable of blocking light without artificial light intensity control, thereby enabling the implementation of this technology.

The research team explained that the key to this achievement is the change in the refractive index of light due to the spaces between polymers, or pores, created when the polymer film is stretched.

In other words, as the amount of light passing through decreases, the transparent film appears opaque.

The film developed by ETRI researchers is 5cm x 5cm in size and blocks 100% of light even if its length is increased by only about 15–30% depending on the wavelength of visible light.

It is hundreds of times better performance compared to existing films with similar performance.

It is also groundbreaking that light intensity can be controlled using only simple mechanical stimulation without using electricity.

In addition, this technology is identical to the general manufacturing process of domestic polymer film manufacturers, so it can be easily manufactured using existing equipment.

It is advantageous for commercialization as a separate nanoparticle dispersion procedure for controlling light transmittance is eliminated, and large-area fabrication is also easy.

“This achievement allows for easy film manufacturing and easy control depending on the degree to which the film is stretched.” Shin Hyung-cheol, Head of the Human Augmentation Research Lab at ETRI, said, “This achievement makes film manufacturing easy and enables easy control depending on the degree to which the film is stretched.” "Once the application is developed in the future, it can be utilized as a material for conveying information through visual and tactile data by varying the tactile sensations by zone," he said.

In addition, this technology is scheduled to be transferred to polymer film material manufacturers, display manufacturers, and others.

This achievement was researched as part of the Ministry of Science and ICT's 'Research on Source Technologies for Human-Centered Autonomous Intelligent Systems' project.

The research team has filed patents for this technology in five countries, including South Korea, the United States, Germany, Japan, and China.