As the critical component in the electromagnetic (EM)
wave shielding
and stealth technology, using broadband EM wave absorbers in harsh
environments is still challenging in practical applications. In this
letter, a novel way of realizing the broadband absorbers with a block
building method is proposed to broaden their absorptivity to different
application scenarios. In particular, the synthesis of the self-supported
carbon nanotube–cellulose nanocrystal (CNT–CNC) film,
which acts as a resistive layer, is independent of selecting substrates
during fabrication and assembling. Therefore, replacing the substrates
to meet different application requirements is easy. We experimentally
demonstrate the application of a block building method in realizing
a high temperature-resistant and self-repairing EM wave absorber by
combining the CNT–CNC film with ceramics and supramolecular
thermoplastic urethane substrates, respectively. Moreover, the CNT–CNC
film is compatible with laser etching and further offers a convenient
way of tuning the absorption frequency after incorporating frequency-selective
surface design. The proposed block building method offers insights
into designing multifunctional absorbers.