Enhancing metacomposite properties and electromagnetic interference shielding: exploring the interplay between manufacturing processability of carbon fiber elastomeric composite and permittivity/permeability effects

Aiming to maximize the electromagnetic performance of composite materials based on carbon fibers (CF), this work demonstrates a critical approach regarding important manufacturing parameters of composites, correlating the manipulation of the complex electric permittivity (ε’, ε”) and complex magnetic permeability (µ’, µ”), as well as the increase in the performance of electromagnetic interference (EMI) shielding effectiveness (SE). The electromagnetic characterization of composites based on polydimethylsiloxane (PDMS) reinforced with CF exhibited transitions in electromagnetic properties over the X-band frequency. The materials that are intrinsically dielectric induced the generation of an intense magnetic response and even the characteristic of metacomposite exhibiting negative ε’ and µ”. The samples showed transitions from a double-positive (DPS) medium to a double-negative (DNG) medium (-ε’ and -µ”) or a progression from DPS to a single-negative (SNG) medium (-µ”). Furthermore, some composites have also presented extremely high values of combined electric permittivity, magnetic permeability, Eddy current, and SE of 100.0 dB. The authors highlight the significant influence of composite processability, especially the insulator (PDMS) thickness, enabling the Maxwell–Wagner-Sillars effect and induction of an intense magnetic response. To predict/optimize the electromagnetic performance of composites, we also propose a computational simulation methodology using the Altair FEKO® software and correlate the Smith Chart with the material’s response.