Weakly Radio-Frequency Negative Permittivity of Poly(vinylidene fluoride)/Ti3SiC2 MAX Phase Metacomposites

Abstract

While metal or carbon materials served as conductive phase in fabricating metamaterials or metacomposites have been widely investigated, MAX phases could provide alternative route. In this paper, Poly(vinylidene fluoride)/Ti3SiC2 MAX phase metacomposites with different Ti3SiC2 content were fabricated. Electrical and dielectric properties of metacomposites were analyzed. Percolating phenomenon was observed over the percolation threshold (fc). Below fc, ac conductivity spectra were explained by Jonscher’s power law, indicating hopping conduction behavior. Above fc, ac conductivity of composites follows Drude model, suggesting the metal-like conductive behavior. Weakly negative permittivity behavior was observed and explained by Lorentz and Drude model, suggesting the combinative contribution of induced electric dipole resonance and low-frequency plasmonic oscillation. The impedance performance of composites were also clarified by Nyquist plots and equivalent circuit analysis, manifesting the capacitive-inductive shift of composites. This work presented a novel route to metacomposites with weakly negative permittivity which greatly benefitted the practical applications of MAX phase in metacomposites.