Low dielectric loss in poly (vinyl alcohol)/graphene metacomposite films with negative permittivity prepared by spin coating

Abstract

Low loss has been considered to be difficult to be achieved in negative permittivity metacomposites as conductance loss and plasma oscillation are simultaneous, limiting their practical applications and further thriving development. In this work, the poly (vinyl alcohol) (PVA)/graphene (GR) films were prepared by spin coating, where the distribution of graphene sheets is parallel to the film. Negative permittivity is obtained at relatively high graphene content, its value can be adjusted by changing graphene content and frequency, ranging from −20 to −5000. Importantly, low dielectric loss (tanδ ∼ 0.035) is achieved for metacomposites with negative permittivity as conductance current has been effectively suppressed at high frequency due to the special parallel distribution of graphene sheets in the composite films. This is because these graphene sheets with winding spiral shape function as inductors more than resistors, the characteristic of inductors is suppressing high-frequency current, beneficial to obtaining low dielectric loss. Besides, biocompatibility and mechanical property are also studied, indicating feasible potentials in flexible wearable electronic devices. This work may set an important paradigm for designing low-loss metacomposites by microstructure control, promoting the development of metacomposites with negative permittivity.