A research team led by Prof. JI Shulin from the Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, has developed a method for manufacturing flexible films that can effectively shield electromagnetic waves across a broad frequency range. The films can be produced on a square-meter scale.
"This means we can make thin materials that protect electronic devices from electromagnetic interference," said Prof. JI.
The research was published in ACS Applied Materials & Interfaces and Langmuir.
With the growing use of electronic devices and communication technologies, electromagnetic waves are increasingly common in everyday environments. However, conventional materials for absorbing or shielding these waves often need to be thick to work effectively and typically cover only a limited frequency range. This makes it difficult to develop thin, flexible films that provide broadband protection.
In this study, the team introduced a design called cross-dimensional percolation, which cmbines nanomaterials of different dimensions into a three-dimensional interconnected network. By adding precisely printed conductive patterns, known as metastructures, the researchers enabled the films to control electromagnetic waves across a wider range of frequencies.
The team also developed a manufacturing process combining pressure-assisted filtration, precision inkjet printing and transfer techniques. They improved the films' flexibility by modifying their surface chemistry and developed a conductive ink to ensure accurate printing of the metastructures. The resulting films can withstand repeated folding.
The films achieve electromagnetic shielding effectiveness of more than 100 decibels, demonstrating their strong shielding performance.
The work could support the development of flexible electromagnetic protection materials for wearable devices and sensitive electronic equipment.
Electromagnetic control mechanism of square-meter-scale electromagnetic control films. (Image by JI Shulin)