Key Takeaways & Executive Findings
- •• Developed PAM/PEG/SA/S-CNTs-Na dual network hydrogels with high toughness and strong EMI shielding, achieving compressive strength of 19.05 MPa and average EMI SE of 32.92 dB at 3 mm thickness. • The complete cross-linking strategy and Na+-triggered SA self-assembly significantly enhanced mechanical properties and electrical conductivity of the hydrogels. • The EMI SE of the optimized hydrogel was 113.21% higher than that of PAM/PEG hydrogels, demonstrating its potential for advanced electromagnetic shielding applications. • The hydrogel materials offer arbitrary shape adaptability, self-healing ability, and easy modification, making them promising for wearable electronics and aerospace fields.
Abstract
With the wide application of electromagnetic wave, a high performance electromagnetic shielding material is urgently needed to solve the harm caused by electromagnetic wave. Complete cross-linking strategy is adopted in this paper. Polyacrylamide (PAM) was synthesized by in-situ polymerization of acrylamide (AM) monomer. The obtained PAM was blended with polyethylene glycol (PEG) to prepare PAM/PEG hydrogels and form rigid support structures. Subsequently, the modified carbon nanotubes (S-CNTs) were incorporated into sodium alginate (SA) and PAM/PEG. Finally, Na+ was used to trigger SA self-assembly, which significantly improved the mechanical properties and electrical conductivity of the hydrogels, and prepared PAM/PEG/SA/S-CNTs-Na hydrogels with high toughness and strong electromagnetic interference (EMI) shielding efficiency (SE). The results showed that the compressive strength of PAM/PEG/SA/S-CNTs-Na hydrogel was 19.05 MPa, which was 7.69% higher than that of PAM/PEG hydrogel (17.69 MPa). More encouraging, the average EMI SE of PAM/PEG/SA/S-CNTs-Na hydrogels at a thickness of only 3 mm and a CNTs content of 16.53wt% was 32.92 dB, which is 113.21% higher than that of PAM/PEG hydrogels (15.44 dB).
1. Introduction
With the wide use of communication technology such as computer and mobile phone, people’s daily life and electromagnetic wave have been inseparable. Electromagnetic wave can quickly transmit information and energy, so it is widely used in electronic and electrical engineering, radio communication, medicine, military, and other fields [1–5]. However, electromagnetic wave brings convenience to our life but also brings a lot of harm. For example, the interweaving of different electromagnetic (EM) signals can cause signal distortion [6–7]. If the body absorbs harmful electromagnetic radiation, it will lead to cancer, mental disorders, fetal abnormalities, cardiovascular diseases, and other diseases [8–9]. Various EM radiation sources will cause environmental pollution. Therefore, the harm caused by electromagnetic radiation must be solved immediately, and the use of electromagnetic protective materials (including electromagnetic shielding materials and absorbing materials) to “cut off” the transmission path of electromagnetic waves can effectively protect sensitive objects from the impact of electromagnetic radiation, which is the main way to solve electromagnetic hazards.
Traditional metal materials (such as silver, copper, iron, nickel, and their alloys) are usually used as equipment shielding shells. However, metal-based materials have disadvantages such as poor thermal stability, high density, and high mechanical stress, which limit their application in electromagnetic shielding field [10–13]. Therefore, it is urgent to develop an advanced electromagnetic shielding material with easy machining, high mechanical flexibility, and high controllable electromagnetic shielding efficiency. Studies have found that hydrogel materials have arbitrary shape adaptability and self-healing ability [14–15]. Their internal contains rich water groups, can absorb electromagnetic waves, in addition, hydrogels are easy to fill other functional fillers for modification. Therefore, hydrogel materials have great application prospects in wearable electronic products, aerospace fields, and electromagnetic shielding fields. Polyacrylamide (PAM) is a kind of hydrophilic polymer that has been widely studied. Its internal crosslinking network contains reactive groups such as amide bonds, which is conducive to the formation of hydrogen bonds and the chemical modifications with various types [16–17]. However, PAM hydrogel itself lacks conductive and sufficient electromagnetic shielding properties. Therefore, it is necessary to incorporate relevant functional fillers to impart conductive and electromagnetic shielding ability.
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Kunlan Diao, Yuhuan Xu, Jingyu Du, Teng Zhou, Xiao Zhan, Daohai Zhang, Xiaosi Qi, Shuhao Qin (2025). High toughness and strong electromagnetic shielding properties of PAM/PEG dual network hydrogels. Int. Journal of Minerals, Metallurgy and Materials (矿物冶金与材料学报). https://doi.org/10.1007/s12613-024-3012-7
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Frequently Asked Questions
What is the main achievement of this research?
The research developed PAM/PEG/SA/S-CNTs-Na hydrogels with high toughness and strong electromagnetic shielding, achieving a compressive strength of 19.05 MPa and an average EMI SE of 32.92 dB at only 3 mm thickness.
How were the hydrogels prepared?
The hydrogels were prepared by in-situ polymerization of acrylamide to form PAM, blending with PEG, incorporating modified carbon nanotubes and sodium alginate, and finally triggering SA self-assembly with Na+ ions.
What is the significance of the EMI SE improvement?
The EMI SE of the optimized hydrogel was 113.21% higher than that of PAM/PEG hydrogels, indicating a significant enhancement in electromagnetic shielding performance.
What are the potential applications of these hydrogels?
These hydrogels have potential applications in wearable electronic products, aerospace fields, and electromagnetic shielding due to their high toughness, flexibility, and effective EMI shielding.
What is the role of sodium alginate and Na+ in the hydrogel?
Sodium alginate and Na+ trigger self-assembly, which significantly improves the mechanical properties and electrical conductivity of the hydrogels, contributing to the enhanced performance.
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