Functional nano-units prepared by electrostatic self-assembly for three-dimension carbon networks hosted in CaCu3Ti4O12 ceramics towards radio-frequency negative permittivity

Carbonaceous materials served as functional units have trigged tremendous fundamental and practical interest in preparing electronic composites especially in meta-composites. In this paper, carbon functional nano-units were built by electrostatic self-assembly of carbon nanotubes (CNTs) and carbon black (CB). Three-dimension carbon networks hosted in CaCu3Ti4O12 (CCTO) matrix were constructed by randomizing CNTs/CB nano-units. Negative permittivity was observed when increasing CNTs/CB nanounits contents exceeded the percolation threshold. The negative permittivity behavior considered as deriving from the low frequency plasma oscillation of delocalized electrons in carbon networks was analyzed by Drude model and equivalent circuit model. Besides, the electrical properties influenced by percolating phenomenon including ac conductivity, dielectric loss, and impedance were investigated. This work presents a novel meta-composites with negative permittivity built by CNTs/CB nano-units filling in low-temperature sintering CCTO matrix which extends the fields of meta-composites and will greatly facilitate its practical applications. (c) 2018 Elsevier B.V. All rights reserved.