Polydimethylsiloxane-multiwalled carbon nanotube composite as a metamaterial

Negative permittivity is an exceptional property of metamaterials, which makes them unique class of artificial materials with numerous applications ranging from cloaking to wave filters. In this paper we report about the PDMS (Polydimethylsiloxane)-MWcnt (Multi wall carbon nano tube) composite beyond percolation, as a metamaterial with high negative permittivity. Percolated composite showed high negative permittivity of −2376.62 at 2541.401 Hz and low tangent loss of −0.065 at 1 MHz. The conductivity spectra followed Jonscher's power law, indicating hopping conduction for composites below percolation threshold. Beyond percolation, networking between the MWcnts formed large number of conductive paths resulting in free electron conduction. The impedance studies showed the capacitive-inductive transition in the percolated composite with inductive phase exhibiting negative permittivity.