Strategies for electromagnetic wave absorbers derived from zeolite imidazole framework (ZIF-67) with ferrocene containing polymers

Given the remarkable performances of metal frame works (MOFs) and ferrocene containing polymers (FCPs) in electronic devices, the research on integration of structure and function for collaborative optimization of electromagnetic wave (EMW) absorption are still missing. Herein, surface grafting and main chain polymerization methods have been employed on the FCPs modifying zeolitic imidazolate framework-67 (ZIF-67) respectively. Polydopamine-coated ZIF-67 was precursor for grafting type products (ZIF-67@PDA-Fc), while poly (vinyl ferrocene) was for main-chain type products (ZIF-67@PVF). Furthermore, the calcined products, polyhedron capsules structured Co3O4@C@alpha-Fe2O3 and Co3O4/alpha-Fe2O3@C microwave absorbers were obtained from ZIF-67@PDA-Fc and ZIF-67@PVF for higher performance EMW absorption. The crystal, morphological and chemical structure was detected via XRD, SEM, TEM, FTIR, Raman, XPS techniques. The EMW absorbability was calculated according to transmission line theory. In particular, the minimum reflection loss (RLmin) of Co3O4@C@alpha-Fe2O3 reached -52.2 dB at the thickness of 3.7 mm with effective absorption band (f(E)) 4.4 GHz. It is worth emphasized that the broadest f(E) was 6.6 GHz obtained at 2.5 mm with RLmin reaching -38.4 dB. Additionally, the EMW absorption mechanism was also studied based on the dielectric and magnetic properties. This investigation will push forward further research and practical application of metal organic compounds-based composites.