Ultratransparent, stretchable, and durable electromagnetic wave absorbers

The growing demand for soft robotics, smart displays, and optoelectronics has driven extensive research into expanding the palette of transparent, stretchable, and durable materials and devices. However, existing electromagnetic wave (EMW) absorbers lack one or more of these key attributes. Herein, we present an EMW absorber that combines ultratransparency (94%), high stretchability (824% fracture strain), and remarkable mechanical and environmental durability. This breakthrough is enabled by a phase-separated terpolymer ionogel. Its effective absorption bandwidth (EAB) of 7.85 GHz in the X and Ku bands significantly outperforms that of all other gel-based materials (<6 GHz) and ranks among the best of all absorbers, whether transparent, stretchable, or neither. This ionogel also demonstrates long-term stability alongside other fascinating properties such as hydrophobicity, skin-like modulus, fatigue and puncture resistance, ability to self-clean, and anti-freezing/icing capabilities. These findings add a key element to the palette, paving the way for next-generation transparent, stretchable devices and ionotronics.