Microwave

Quantum mechanics

Magnetic field

Relative permittivity

Polymerization

Materials science

Nuclear magnetic resonance

Plasma

Biochemistry

Polyaniline

Oscillation (cell signaling)

Polymer

Physics

Dielectric

Drude model

Electromagnetic shielding

Condensed matter physics

Diamagnetism

Composite material

Chemistry

Plasma oscillation

Optoelectronics

Permittivity

Composites Science and Technology

Metacomposites have drawn considerable attention due to their enticing prospect in electronic and dielectric devices, which meanwhile unfortunately suffered from extremely high negative permittivity (ε' < 0). Herein, we put forward a strategy to suppress the plasma oscillation in metacomposites and thereby constrain the value of negative permittivity by introducing the semiconductive polyaniline to construct polyaniline/nickel (PANI/Ni) metacomposites. Weakly negative permittivity was obtained at a magnitude of 102 over the whole test frequency band, which is remarkably lower by at least three orders of magnitude than that of most metacomposites. The ε′-negative value was resultantly fine-tuned by about 102 with equally adjusting Ni content. Lorentz and Drude models were employed to describe ε′-negative spectra, indicating that both dielectric resonance and plasma oscillation contributed to negative permittivity. Negative susceptibility of ε′-negative materials was mainly ascribed to high-frequency diamagnetic response within Ni networks. The well-designed PANI/Ni metacomposites with weakly and fine-tuning negative permittivity can greatly benefit the practical applications on electromagnetic (EM) shielding, microwave absorption and novel EM sensors.

Ultraweakly and fine-tunable negative permittivity of polyaniline/nickel metacomposites with high-frequency diamagnetic response