With the advent of the fourth industrial revolution era, flexible or retractable electronic devices will continue to emerge. As the substrate of the second generation of wearable electronic devices, the electronic skin is attached to human skin, so that it is flexible, adherent and comfortable to wear. It is very important. In order to reflect these advantages, the development of flexible electrodes (conductors) that can be freely deformed has attracted widespread attention in the industry.
Recently, the team of Dr. Jae/Min Hong from the Korea Institute of Science and Technology (KIST) Institute of Composite Materials Technology combined a hydrogel-degradable plastic (Ecoflex) composite with a silver electrode to develop a high-expansion electrode. The performance can be increased by a maximum of 18.8. More than doubled, reaching the world's leading level.
It is important that the flexible electrode maintains its electrical characteristics under the deformed conditions. In order to ensure the electrical properties, flexible preparation of metal materials, the predecessors have conducted a lot of research. The core of the flexible element is the flexible electrode, its printing The preparation process has certain advantages in terms of specific volume. The ink jet used in the printing process can ensure that the flexible electrode can maintain its performance under stretching conditions. The ink-jet is produced by mixing micron-sized particles and macromolecules. In order to ensure the conductivity, the complexes are mainly made of metallic materials such as silver and gold.
Flexible electrodes that can usually be printed are prepared on a silicon-based, elastically degradable plastic substrate such as polydimethylsiloxane (PDMS), but when such materials are in contact with human skin or other tissues, they are worn due to low deformation rates. Feeling is not good. The research team used a hydrogel material with a high deformation rate and similar texture to the skin, but due to the traditional process it is difficult to print a metallic substrate material such as silver on the hydrogel, thus, in the hydrogel A thin layer of degradable plastic was coated and combined with a silver ink jet. The thickness of the degradable plastic of this surface treatment method was 30 μm, which was equivalent to only half that of hair. A high stretchable electrode was thus developed.
The high-expansion electrode developed this time can be printed according to the pattern desired by the user, and is advantageous in forming a multi-area circuit. Unlike existing electrodes, it is prepared on a highly stretchable substrate with a very high degree of deformation and is in contact with human body. As an electronic skin, it is more comfortable to wear and the performance of flexible electrodes has reached the world's leading level.
Dr. KIST Jae/Min Hong said that in the future this technology is expected to be used in areas such as electronic skin and medical instruments, which will contribute to the innovation of wearable devices and flexible robots. In addition, this research has been supported by the Korea Ministry of Industry, Commerce and Resources as The core industrial technology development project has also received the support of the Korea Ministry of Science, Technology, and Information, as a joint project of the KIST organization. The research results have been published in the internationally renowned journal Advanced Materials.