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

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.