Transparent and Environmentally Adaptive Semi-interpenetrating Network Hydrogels for Electromagnetic Interference Shielding

Abstract

In this work, by constructing a semi-interpenetrating network (semi-IPN) structure, one type of transparent and environmentally adaptive polyacrylamide (PAM)/poly(vinyl alcohol) (PVA)/ LiCl semi-IPN hydrogel with effective electromagnetic interference (EMI) shielding performance and good mechanical properties was successfully fabricated. The addition of lithium chloride effectively enhanced the antidehydration and antifreezing performance of PAM/ PVA hydrogels. As the initial LiCl concentration was 12 mol/L, the semi-IPN hydrogel retained its water for 30 h at 25 °C and 30% RH and still exhibited good flexibility at −50 °C. Moreover, LiCl-containing semi-IPN hydrogels showed an attractive electrical conductivity of 13.19 S/m at 25 °C and effectively absorbed the incident electromagnetic wave, which was dominant in the total EMI shielding efficiency beyond 35.6 dB. The PAM/PVA semi-IPN hydrogels loaded with LiCl also possessed good transparency (light transmittance >89%). The flexible and transparent EMI shielding materials may have broad prospects in the field of wearable electronic devices.

Dynamic Metal-Coordinated Adhesive and Self-Healable Antifreezing Hydrogels for Strain Sensing, Flexible Supercapacitors, and EMI Shielding Applications

“…The total shielding efficiency (SE) was measured using various scattering parameters (S 11 , S 12 , S 21 , S 22 ) and equation 7 of the Supporting Information, which measures the attenuation of electromagnetic waves passing through the hydrogel . At a frequency of 20 GHz, the AM 20 -Ca 2+ hydrogel displayed a total shielding efficiency (SE) of ∼35 dB (Figure A), which is far exceeding the industrial standard of 20 dB. − This value also surpassed that of many other conducting filler-based elastomeric and hydrogel materials used for electromagnetic interference (EMI) shielding applications ,− ,− (Table S4). This exceptional EMI shielding ability of the AM 20 -Ca 2+ hydrogel may be attributed to three key factors: high water content (∼74%), a porous network, and adequate ionic conductivity.…”

A PDMS pocket based transparent polydopamine-decorated polypyrrole nanofibril–polyacrylamide hydrogel for EMI shielding applications

“…25 Jia et al 26 prepared CA/AgNW/PU film with a high optical transmittance of 92% and achieved an EMI SE of 20.7 dB. Yuan et al 27 prepared a PAM–PVA–LiCl hydrogel, which showed absorption dominant EMI shielding performance beyond 35.6 dB. Zhou et al 28 prepared a PAM–PVA–GO–LiCl composite hydrogel that exhibited superior anti-dehydration and electromagnetic shielding (EMI) capabilities exceeding 37.2 dB.…”