Transparent organogel based on photopolymerizable magnetic cationic monomer for electromagnetic wave absorbing

Abstract

The application of conventional absorbing materials is limited due to complex preparation process and poor transparency caused by fillers. In this study, a highly transparent ionic organogel was prepared by photocuring a dimethyl sulfoxide (DMSO) solution of a polymerizable magnetic cationic monomer [DAC]5[Dy(NCS)8]. Both components of organogel, which are the photopolymerizable magnetic cationic monomer and polar solvent DMSO, have an important effect on the magnetic losses and dielectric losses properties of the organogel respectively. By tuning the mass ratio of DMSO to the monomer and the content of the cross-linker, the complex permittivity of the gel could be effectively adjusted to improve the impedance matching, and finally a gel with excellent wave absorption properties and good tensile properties was obtained. The optimum organogel was fabricated with a minimum reflection loss of −45.9 dB and a broadest effective absorption bandwidth (EAB) of up to 5.2 GHz, and effective absorption in the millimeter band (26.5–40 GHz) which is within the fifth generation (5G) mobile networks. With the advantages of simple preparation method, arbitrary shape and good adhesion to a variety of substrates and complex surfaces, this multifunctional gel provides a new solution for complex scenarios requiring optical transparency and simultaneous absorption of electromagnetic waves.