Poly(dimethylsilylene)diacetylene-Guided ZIF-Based Heterostructures for Full Ku-Band Electromagnetic Wave Absorption

Zeolitic imidazolate frameworks (ZIFs), a group of metal–organic frameworks (MOFs), hold promise as building blocks in electromagnetic (EM) wave absorption/shielding materials and devices. In this contribution, we proposed a facile strategy to synthesize three dimensional ZIF-67-based hierarchical heterostructures through coordinated reacting a preceramic component, poly(dimethylsilylene)diacetylenes (PDSDA) with ZIF-67, following by carbonizing the PDSDA wrapped ZIF at high temperature. The introduction of PDSDA leads to a controllable generation of surface network containing branched carbon nanotubes and regional distributed graphitic carbons, in addition to the nanostructures with well-defined size and porous surface made by cobalt nanoparticles. The surface structures can be tailored through variations in pyrolysis temperatures, therefore enabling a simple and robust route to facilitate suitable structural surface. The heterostructure of ZIF nanocomplex allows the existence of dielectric loss and magnetic loss, therefore, yielding a significant improvement on EM wave absorption with a minimum reflection coefficient (RCmin) of -50.9 dB at 17.0 GHz at a thickness of 1.9 mm and an effective absorption bandwidth (EAB) covering the full Ku-band (12.0 GHz to 18.0 GHz).