Understanding the negative permittivity behavior of polyvinyl alcohol based metamaterials under radio frequency

Functional metamaterials that exhibit negative dielectric permittivity through percolative network formation have attracted immense attention due to their significant potential for a wide range of applications in electronic devices. Negative permittivity has taken off as a research topic recent years in percolative composites. The polymer nanocomposites (PVA/H-Pa-G) were prepared using the α-Fe ₂O ₃ modified GNP and HCl doped polyaniline (Pani) based nanofillers (H-Pa-G). The as prepared samples were characterized in order to analyze their dielectric response for understanding the negative permittivity behavior. Below the percolation threshold for the polymer nanocomposite with 0.10%, 0.25% H-Pa-G nanofiller weight fraction, an increase in σ _ac conductivity is observed with increase in frequency. The dielectric study confirmed the negative permittivity behavior for the polymer nanocomposite (0.50%, 1.00% and 2.00%) above the percolation threshold. This can be mainly attributed to the presence of the conductive network of H-Pa-G nanofiller in the PVA matrix. On the contrary, the positive permittivity is due to the insulative nature of PVA matrix. The empirical data of real permittivity was fitted using the Drude model that corresponded well with the experimental data with the f _p = 1.31 GHz which is further certified by the equivalent circuit model fitting. This proposed work strongly suggest the implication of the as prepared polymer nanocomposite for the negative permittivity materials based applications.