Synthesis of TiO₂/MWCNTs nanocomposites by click chemistry and its microwave absorption properties

Titanium dioxide/multi-walled carbon nanotubes (TiO₂/MWCNTs) are nanocomposites (NCs) prepared via click reaction of TiO₂ nanoparticles (TiO₂ NPs) with azide groups (TiO₂–N₃) on the surface and MWCNTs with alkynyl groups (MWCNTs–ALK) on the surface. The phase structure, graphitization degree, structure, elemental composition, the microstructure of TiO₂/MWCNTs NCs were characterized by XRD, Raman, IR, XPS and SEM, and their electromagnetic (EM) parameters were determined by the vector network analyser. For TiO₂/MWCNTs NCs with click reaction, the minimum reflection loss (RL_min) is up to −47.87 dB at 12.02 GHz, the matching thickness is 2.0 mm, and the bandwidth is lower than −10 dB in the range of 7.7–12.48 GHz. Compared with the physically mixed TiO₂/MWCNTs composites, TiO₂/MWCNTs NCs prepared by click reaction show more excellent EM absorption properties, which is mainly due to the binding of covalent bonds between the two kinds of materials that lead to the enhancement of interfacial effects, the improvement of impedance matching and the increase of electron migration.