Electromagnetic shielding of Optically-Transparent and Electrically-Insulating ionic solutions

Junpyo Hong, Jisung Kwon, Aamir Iqbal, Daesin Kim, Taehoon Kwon, Pradeep Sambyal, Soon Man Hong, Ho Gyu Yoon, Myung Ki Kim, Chong Min Koo

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


High-tech electronic and communication devices require advanced materials for their protection against electromagnetic interference (EMI). Electrically conductive solid materials, such as metals, are typically employed as EMI shields owing to their high shielding performance caused by their high electronic conductivity. Herein, electrically insulative and ionically conducting aqueous ionic solutions of KBr, NaCl, and CaCl2 salts are investigated with a focus on their effective EMI shielding performance, which is mechanistically different from that of conventional solid materials. A 5M KBr solution exhibits an optimal EMI shielding effectiveness of 61.3 dB at 5-mm thickness. Debye and Drude theoretical models, which describe polarization of dipolar water molecules and ionic conduction of mobile ions, respectively, are invoked to elucidate the absorption-dominant EMI shielding mechanism of the optically transparent aqueous ionic solutions in X-band (8.2–12.4 GHz) frequency range. Cost-effective aqueous ionic solutions can be used as efficient and lightweight EMI shielding materials providing strong optical transparency in advanced electronic systems.

Original languageEnglish
Article number135564
JournalChemical Engineering Journal
Publication statusPublished - 2022 Jun 15

Bibliographical note

Funding Information:
This work was supported by a grant from the Basic Science Research Program (2017R1A2B3006469, 2022R1A2C3006227, and 2021M3H4A1A03047327) through the National Research Foundation of Korea, funded by the Ministry of Science, ICT and Future Planning, Republic of Korea. This work was partially supported by the KU-KIST Research and KIST Internal Grand Challenge programs, funded by the Korea Institute of Science and Technology (KIST).

Publisher Copyright:
© 2022 Elsevier B.V.


  • Debye-Drude model
  • Dipole polarization
  • Electromagnetic shielding
  • Ionic conduction
  • Ionic solutions

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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