Atomically thin 2D graphene sheets exhibit unparalleled in-plane stiffness and large out-of-plane elasticity, thereby providing strong mechanical resonance for nanomechanical devices. The exceptional resonance behavior of ultrathin graphene, which promises the fabrication of superior acoustic absorption materials, however, remains unfulfilled for the lack of applicable form and assembly methods. Here, a highly efficient acoustic absorber is presented, wherein cellular networks of ultrathin graphene membranes are constructed into polymer foams. The ultrathin graphene drums exhibit strong resonances and efficiently dissipate sound waves in a broad frequency range. A record specific noise reduction coefficient (51.3 at 30 mm) is achieved in the graphene-based acoustic absorber, fully realizing the superior resonance properties of graphene sheets. The scalable method facilely transforms commercial polymer foams to superior acoustic absorbers with a ≈320% enhancement in average absorption coefficient across wide frequencies from 200 to 6000 Hz. The graphene acoustic absorber offers a convenient method to exploit the extraordinary resonance properties of 2D sheets, opening extensive new applications in noise protection, building design, instruments and acoustic devices.
Keywords: acoustic absorbers; cellular materials; graphene; ultrathin drums.
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