Polarization-driven multifunctional organohydrogels with strain sensitivity toward electromagnetic wave absorption

Rapid advancements in flexible electronics and military applications necessitate high-performance electromagnetic wave (EMW) absorbers. While huge breakthroughs in achieving high-attenuation microwave absorption, conventional EMW absorbing materials have single function and ambiguous absorption mechanisms. Herein, numerous gel-type absorbers are fabricated by introducing “regulators” into poly(acrylamide-co-acrylic acid) (P(AM-co-AA)) networks through radical polymerization in a glycerol-water mixed solvent. The dielectric constant and EMW absorption performance of the gels are precisely predicted by adjusting monomer concentration, the ratio of glycerol/water, and the content of the regulators. Notably, A₆G₂₀T₂₀-2 exhibits promising absorption performance with a minimum reflection loss (RL_min) of –33.8 dB at 12.4 GHz. The effective absorption bandwidth (EAB) covers the entire X-band (8.2–12.4 GHz) at a thickness of 2.7 mm. A₆G₂₀T₂₀-2 also has sensitive deformation responses and excellent tensile strength, adhesiveness, self-healing and anti-freezing properties. Overall, this work not only provides insight into the polarization loss mechanism of the gels as the result of high correlation between EMW absorbing properties and molecular polarization, but also offers an important reference for developing functional protective materials because of the rich functionalities and efficient protective capabilities of the gels.