Hydrogel-based composites beyond the porous architectures for electromagnetic interference shielding

Abstract

With the rapid development of the electronic industry and wireless communication technology, electromagnetic interference (EMI) or pollution has been increasingly serious. This not only severely endangers the normal operation of electronic equipment but also threatens human health. Therefore, it is urgent to develop high-performance EMI shielding materials. The advent of hydrogel-based materials has given EMI shields a novel option. Hydrogels combined with conductive functional materials have good mechanical flexibility, fatigue durability, and even high stretchability, which are beneficial for a wide range of applications, especially in EMI shielding and some flexible functional devices. Herein, the current progress of hydrogel-based EMI shields was reviewed, in the meanwhile, some novel studies about pore structure design that we believe will help advance the development of hydrogel-based EMI shielding materials were also included. In the outlook, we suggested some promising development directions for the hydrogel-based EMI shields, by which we hope to provide a reference for designing hydrogels with excellent EMI shielding performance and multifunctionalities.

Elastomer Encapsulated Silver Nanorod Dispersed Polyacrylamide-Alginate Hydrogel for Water-Pressure-Dependent EMI Shielding Application

“…However, the performance of EMI shielding depends on many factors, for example, conductivity of hydrogels, polarization loss capabilities, and multiple reflections of incident EMWs. Most functional materials can be easily and uniformly dispersed in hydrogels to form conductive pathways, contributing to the high conductive loss of the incident EMWs . It has already been reported that if there are enough water-rich environments along with moderate conductive properties, enhanced attenuation of penetrated waves provides absorption dominated EMI shielding performance.…”

“…Most functional materials can be easily and uniformly dispersed in hydrogels to form conductive pathways, contributing to the high conductive loss of the incident EMWs. 45 It has already been reported that if there are enough water-rich environments along with moderate conductive properties, enhanced attenuation of penetrated waves provides absorption dominated EMI shielding performance. The total electromagnetic shielding effectiveness (SE T ) is the sum of the shielding effectiveness due to the reflection component (SE R ), the absorption component (SE A ), and/or the internal multiple reflection component (SE M ).…”

Biopolymer‐Based Aerogels for Electromagnetic Wave Shielding and Absorbing

“…Moreover, the proposed biomimetic honeycomb microstructure greatly enhanced the reflection and dissipation of EMWs, which had been illustrated in previous reports. [ 43‐44 ] Finally, this aerogel exhibited remarkable SSE and SSE/ d up to 30660 dB·cm 3 ·g –1 and 189400 dB·cm 2 ·g –1 , respectively.…”

Enhanced Microwave Absorption Performance of α-FeOOH Nanorods on Carbon Aerogel Powder

“…Nowadays, wireless electronic equipment is in a high-speed development stage in all fields. , From the massive use of mobile phones, Wi-Fi, and 5G technologies in daily life to radars and stealth fighters in the national defense industry, electromagnetic waves (EMW) can be seen everywhere and play an irreplaceable role. , However, the widespread use of EMW has seriously affected human health and military security while benefiting mankind. Unwanted EMW has become the fourth largest source of pollution in the world, which has raised concerns about addressing the hazards of leaking electromagnetic radiation .…”