Polymerizable Ionic Liquids Enable Proton-Ion Cooperative Interactions in Transparent Hydrogels for...

Transparent electromagnetic wave (EMW) absorbing materials are highly desirable for emerging optoelectronic and electromagnetic protection technologies, yet simultaneously achieving high optical transparency, strong interfacial adhesion, and efficient EMW attenuation remains challenging due to the intrinsic trade-off between dipole alignment and interfacial mobility. Here, we report a molecular design strategy based on proton-ion cooperative interactions to construct a reconfigurable polar network in a transparent polyelectrolyte hydrogel. By incorporating polymerizable choline-proline ionic liquids (CPILs) into a hydrogen-bonded poly(acrylic acid) (PAA) matrix, the spatial distribution and orientation dynamics of polar moieties are regulated through synergistic covalent and dynamic noncovalent interactions. These proton-ion cooperative interactions enable simultaneous enhancement of dielectric polarization and interfacial adhesion within a single transparent network. Consequently, the hydrogel achieves an effective electromagnetic absorption bandwidth of 6.5 GHz and a minimum reflection loss of -49.31 dB, while maintaining an average visible-light transmittance exceeding 96% and a shear adhesion strength of 7.71 MPa on glass substrates. This work establishes a molecular-level design paradigm for coupling dielectric polarization and interfacial adhesion in transparent soft materials, providing new opportunities for flexible electronics and transparent electromagnetic wave absorption.