Smart Shape Memory Composite Foam Enabled Rapid and Conformal Manipulation of Electromagnetic Wave Absorption Performance

Abstract

With the development of communication and electronic technologies, smart electromagnetic wave (EMW) absorption materials with tunable performance are highly desired for the applications in complicated electromagnetism circumstances. However, the performance of ordinary EMW absorption materials is determined by their electromagnetic parameters, which are constant unless the composition changes. This study presents a porous EMW absorption material with adjustable effective absorption bandwidth (EAB) and reflection loss (RL) to meet the requirements in tunability for complex electromagnetic applications. A composite foam is first fabricated by assembling reduced graphene oxide (rGO) to the melamine sponge (MS) framework. Furthermore, thermoplastic polyurethane (TPU) is introduced and endows the MS/rGO with the thermoresponsive property after crosslinking. The prepared MS/rGO shows high flexibility, elasticity, and low density of 10.7 mg cm-3, and reaches the minimum RL of -63.29 dB with effective bandwidth of 7.18 GHz. Tunable EMW absorption performance of MS/rGO-TPU is achieved through the shape memory effect and the EAB can be adjusted in a wide range from 5.5 to 18 GHz upon compression deformation, which can be modulated by cooling/heating, while the minimum RL can be switched from -15.4 to -39.2 dB. In summary, the lightweight MS/rGO and smart MS/rGO-TPU with adjustable performance for EMW absorption are expected to provide various options in complex electromagnetic applications.

Keywords: electromagnetic wave absorption, shape memory, adjustable performance, composite foam