Constructing highly directional multilayer cell structure(HDMCS) towards broadband electromagnetic absorbing performance for CNTs/PMMA nanocomposites foam

The highly directional and multilayer cell structure (HDMCS) was achieved in carbon nanotubes (CNTs)/PMMA nanocomposites via the one-step physical constraint foaming technology. The influence of HDMCS on dielectric properties and electromagnetic absorption performance of CNTs/PMMA foam were investigated, respectively. The results show that when the dielectric constant of CNTs/PMMA foam with HDMCS was reduced, the dielectric loss could be kept stable. The main reason is the HDMCS, which makes the effects of interfacial polarization are mutual restricted and compensated in the direction of parallel and vertical interface. It proposes that the dielectric constant and dielectric loss of multilayer nanocomposites foam could achieve independently regulation. The absorbing bandwidth of the CNTs/PMMA foam with HDMCS was 2.5 GHz (9.1–11.6 GHz), which was wider than 1.7 GHz of the monolayer foam with the thickness of 2 mm. The excellent EMA performance of CNTs/PMMA foam with HDMCS is attributed to the improved impedance match and the multiple reflection mechanisms. This effort demonstrates a feasible and effective approach for the design and fabrication of light weight and good microwave absorption materials.