Active control of graphene-based membrane-type acoustic metamaterials using a low voltage.

Membrane-type acoustic metamaterials for acoustic insulation applications have been attracting ever increasing attention. However, the first anti-resonant frequency of these acoustic metamaterials is fixed once the membrane type is chosen. Here, we propose a novel yet convenient strategy to actively adjust the anti-resonant frequency of the membrane. The poly(vinyl alcohol)/graphene (PVA/GR) nanocomposite membrane is introduced into the acoustic metamaterial, the effective modulus of which is tunable by applying an external electric field. As a result, the first anti-resonant frequency of membrane-type acoustic metamaterials can be actively tuned between 369.2 to 420 Hz, leading to excellent sound attenuation properties. The noise reduction frequency can be actively modulated by DC voltage. Moreover, the change in frequency is consistent with the modulus variation of the PVA/GR nanocomposite membrane when the graphene concentration is varied. In addition, the conductive PVA/GR nanocomposite membrane also exhibits good electromagnetic interference shielding performance in the frequency range of 8-12 GHz. Being actively tunable by an external electric field, this PVA/GR nanocomposite membrane-based acoustic metamaterial is very promising for use in frequency-tunable acoustic insulation applications.