Strongly plasticized gelatin-based hydrogel for flexible encapsulation of complex-shaped electronic devices.

ABSTRACT

The growth of environmentally sensitive complex-shaped electronic devices (ECEDs) has led to a surging demand for flexible electromagnetic wave (EMW) absorbers. Herein, the water loss property of hydrogel was ingeniously applied for the flexible encapsulation (FE) of ECEDs. To be specific, saturated state (SGT) hydrogels were prepared by chemical cross-linking, and the hydrogen bond dissipation network promoted FE. Additionally, SGT has an effective absorption bandwidth (EAB) of 6.04 GHz at 1.65 mm due to the presence of dipole polarization. With the loss of water, SGT transitions to its natural state (NGT), and the decreasing conductivity leads to better impedance matching. NGT exhibited a broader EAB (9.20 GHz at 2.65 mm) and also strength and lightness (density of 0.3 g cm-3). Furthermore, the semi-automatic reversible cyclic transformation between SGT and NGT gels further broadens application scenarios. GT gel combines self-encapsulation and self-optimized performance as a potential EMW absorber for FE.