Journal Article

Lithium chloride-driven enhanced conductivity of silicone-encapsulated polyacrylamide/alginate/ionic liquid-based transparent hydrogel for high-performance pressure-sensitive EMI shielding applications

Khatua, Bhanu Bhusan, De, Anurima, Mondal, Ankita, Singh, Prem Pal

2023

Overview

Tunable, wearable and transparent electromagnetic interference (EMI) shielding materials are seeking great research interest in the fabrication of smart EM devices. In this context, the exploitation of multifunctional hydrogels with excellent mechanical and transparent properties along with EMI shielding effectiveness is an emerging alternative and a great challenge as well. Here, we report a flexible, transparent and pressure-sensitive EMI shielding material with excellent mechanical properties (tensile strength ~ 1.53 MPa) based on the synergistic effect of ionic compounds such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and lithium chloride (LiCl)-loaded hydrogel-elastomer, i.e., polyacrylamide (PAM)/sodium alginate (Alg)-PDMS hybrid. The synergistic effect induced by IL and LiCl in PAM-Alg hydrogel alters the ionic conductivity as well as EMI shielding effectiveness (SE) (~ 45.76 dB) performance, which are higher than the corresponding PAM-Alg (~ 28.12), PAM-Alg-IL (~ 38.11 dB) and PAM-Alg-Li hydrogel (~ 32.98 dB). Furthermore, the fabricated hydrogel (IL and LiCl in PAM-Alg) showed a decrement in relative resistance change under different physical compression. Interestingly, the EMI SE of the ion-loaded hydrogel is ~ 65.08 dB under physical compression and ~ 46.99 dB after release. It also showed the EMI SE T (total EMI shielding effectiveness) value of ~ 23.81 dB at freezing conditions. However, to check the sustainability of the hydrogel under a harsh environment, a thin PDMS layer was formed on its surface with a little sacrifice of EMI SE T of ~ 4 dB than the unwrapped one. Thus, these findings explore an innovative strategy to fabricate a smart EMI shielding material for futuristic development in innovative electronics. Graphical Abstract

• Publisher: Springer US,Springer,Springer Nature B.V
• Subject: alginates / Characterization and Evaluation of Materials / Chemistry and Materials Science / Classical Mechanics / Crystallography and Scattering Methods / Effectiveness / Elastomers / Electric properties / Electromagnetic interference / Electromagnetic shielding / Electromagnetism / electronics / Freezing / Hydrogels / Ion currents / Ionic liquids / lithium / Lithium chloride / Lithium compounds / Materials Science / Mechanical properties / Polyacrylamide / Polymer Sciences / Polymers & Biopolymers / Silicones / Sodium alginate / Solid Mechanics / synergism / Synergistic effect / Tensile strength